1,721,016 research outputs found
Time and space model of urban pollution migration: Economy-energy-environment nexus network
No full textIn recent years, news of “cancer villages” in the Huaihe River Basin filled front and back pages of newspapers and generated elevated concern among readers. This study aims to understand the relationship between the “cancer villages” and the “large cities” around them. A gravity model is constructed to analyze the correlation between “big cities” and “cancer villages” in terms of indices involving economic connections and pollution frequency. Direct and indirect environmental relationships between large cities and “cancer villages” are analyzed using ecological network analysis, in particular the utility analysis method. Results of the pollution-utility analysis showed that cities distant from “cancer villages” can also affect the county through indirect connections. Based on the pollution utility relationship, we found that “cancer villages” both affect and are affected by cities through indirect feedback relationships. It can be inferred that “cancer villages” have a high incidence of malignant disease not only because of the pollution from its surrounding cities but also because of the influence of far-away cities through a network of interactions. In this way, the pollution of “cancer villages” may be heightened with harmful consequences to population health. Considering these indirect connections, not all of the “cancer villages” are able to reduce their pollution by transferring it to another city or county because it can return through indirect pathways. The best approach would be to lower the pollution generation in the first place in order to prevent its impacts, as well as to at least partially mitigate them through more effective medical care
Ecosystem Health Indicators—Freshwater Environments
No full textFreshwater environments around the globe are under threat from increasing anthropogenic stress, including nutrient enrichment, urbanization, industrial waste, deforestation, water abstraction, flood prevention engineering, sedimentation, dam construction, climate change and invasive species. If freshwater ecosystem health is to be safeguarded, then measuring and monitoring change will be critical for effective management. Ecosystem health is the maintenance of structure and function in the face of external stress, this includes both biotic and abiotic components. This chapter summarizes the main groups of indicators commonly used to assess ecosystem health
Habitat Mapping
No full textOrganisms inhabit a space that suits their needs; the structure and spatial arrangement of habitats constrain, and can potentially become predictors of, species distribution, abundance, and richness. In recent decades, the importance of mapping habitats has been increasingly recognized in ecological research and in contexts like conservation and management. This entry looks at geomatics-based habitat mapping approaches, i.e., approaches supported by the use of Geographic Information Systems (GIS), remotely sensed data representing potential surrogates of species distribution, and spatial analysis. Characteristics of abiotic, single species, and community habitat maps are introduced and linked to three common approaches to habitat mapping: abiotic, top-down (unsupervised), and bottom-up (supervised) habitat mapping. Important considerations for habitat mapping, including scale and data quality, are also discussed: habitat maps are very sensitive to the decisions made by map producers, which highlights the need to remain critical of mapping outputs. Perspectives on the future of habitat mapping are provided, as geomatics-based habitat mapping is a relatively recent and rapidly evolving field. Advances in spatial sciences will help habitat map producers address the current challenges of their field and develop new approaches to improve understanding of habitat structure and function through habitat maps across all types of ecosystems
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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
Estuarine ecohydrology
No full textThroughout the world, estuaries and coastal waters have experienced environmental degradation. Present proposed remedial measures based on engineering and technological fix have been unable to restore the ecological processes of a healthy, robust estuary and, as such, will not reinstate the full beneficial functions of the estuary ecosystem. The successful management of estuaries and coastal waters requires ecological engineering, that is, an ecohydrology-based, basin-wide, approach. Ecohydrology is the science that relates hydrological processes to the biological dynamics of ecosystems at various spatial and temporal scales. The ecohydrology concept was developed in the framework of UNESCO’s International Hydrological
Programme (IHP). It hypothesized and empirically confirmed in a number of demonstration sites that the ecological services of rivers and lakes can be restored by using hydrology to regulate biota dynamics and vice versa. The synergic integration at the basin scale of various ecohydrological measures based on ecological needs provides the scientific background for twinning ecosystem variables in order to enhance the carrying capacity and the resilience of ecosystems while promoting positive socioeconomic feedbacks
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