1,721,159 research outputs found
Exploring unintended feedbacks between coastal hazard, exposure, and vulnerability
No full textCoastal zones are more densely populated than any other landscape on Earth. These regions are also dynamic places that naturally change shape and position, especially in response to sea-level rise, leaving the infrastructure that sustains high coastal populations exposed to natural coastal hazards. Therefore, to make exposed infrastructure less vulnerable to damage, shorelines are deliberately altered with hazard protections. Some developed coasts have been altered on such spatial scales that they no longer act like natural coastlines. Instead, they function as coupled human-landscape systems, where shoreline dynamics reflect interactions and feedbacks between human alterations and natural coastal processes. The Atlantic Coast of the USA has over 2500 km of developed coastline, and is arguably the largest coastal coupled human-landscape system in the world, and is dominated by beach nourishment: a type of coastal hazard protection that involves widening an eroding beach with imported sand. Beach nourishment buffers exposed infrastructure from coastal hazards, and also serves as a stock of natural capital for tourism economies. However, despite ubiquitous nourishment along the US Atlantic since the 1960s, coastal risk continues to increase. This dynamic is an expression of the “safe development paradox”, in which exposure to hazard continues to rise, despite increased efforts to protect against hazard impacts. This thesis explores unintended feedbacks between coastal hazard, exposure, and vulnerability evident along the US Atlantic Coast. My work examines why beach nourishment might have the counter-productive consequence of increasing risk. This thesis also presents a conceptual framework that may enable future models of coastal risk to incorporate “big data” approaches to illuminate and explore the “safe development paradox”, and to test whether prospective management strategies might mediate coastal risk or exacerbate it
Reconstructing patterns of coastal risk in space and time along the US Atlantic coast, 1970–2016
No full textDespite interventions intended to reduce impacts of coastal hazards, the risk of damage along the US Atlantic coast continues to rise. This reflects a long-standing paradox in disaster science: even as physical and social insights into disaster events improve, the economic costs of disasters keep growing. Risk can be expressed as a function of three components: hazard, exposure, and vulnerability. Risk may be driven up by coastal hazards intensifying with climate change, or by increased exposure of people and infrastructure in hazard zones. But risk may also increase because of interactions, or feedbacks, between hazard, exposure, and vulnerability. Using empirical records of shoreline change, valuation of owner-occupied housing, and beach-nourishment projects to represent hazard, exposure, and vulnerability, here we present a data-driven model that describes trajectories of risk at the county scale along the US Atlantic coast over the past 5 decades. We also investigate quantitative relationships between risk components that help explain these trajectories. We find higher property exposure in counties where hazard from shoreline change has appeared to reverse from high historical rates of shoreline erosion to low rates in recent decades. Moreover, exposure has increased more in counties that have practised beach nourishment intensively. The spatio-temporal relationships that we show between exposure and hazard, and between exposure and vulnerability, indicate a feedback between coastal development and beach nourishment that exemplifies the “safe development paradox”, in which hazard protections encourage further development in places prone to hazard impacts. Our findings suggest that spatially explicit modelling efforts to predict future coastal risk need to address feedbacks between hazard, exposure, and vulnerability to capture emergent patterns of risk in space and time
Masked shoreline erosion at large spatial scales as a collective effect of beach nourishment
No full textSea‐level rise along the low‐lying coasts of the world's passive continental margins should, on average, drive net shoreline retreat over large spatial scales (>102 km). A variety of natural physical factors can influence trends of shoreline erosion and accretion, but trends in recent rates of shoreline change along the U.S. Atlantic Coast reflect an especially puzzling increase in accretion, not erosion. A plausible explanation for the apparent disconnect between environmental forcing and shoreline response along the U.S. Atlantic Coast is the application, since the 1960s, of beach nourishment as the predominant form of mitigation against chronic coastal erosion. Using U.S. Geological Survey shoreline records from 1830–2007 spanning more than 2500 km of the U.S. Atlantic Coast, we calculate a mean rate of shoreline change, prior to 1960, of ‐55 cm/yr (a negative rate denotes erosion). After 1960, the mean rate reverses to approximately +5 cm/yr, indicating widespread apparent accretion despite steady (and, in some places, accelerated) sea‐level rise over the same period. Cumulative sediment input from decades of beach nourishment projects may have sufficiently altered shoreline position to mask "true" rates of shoreline change. Our analysis suggests that long‐term rates of shoreline change typically used to assess coastal hazard may be systematically underestimated. We also suggest that the overall effect of beach nourishment along of the U.S. Atlantic Coast is extensive enough to constitute a quantitative signature of coastal geoengineering, and may serve as a bellwether for nourishment‐dominated shorelines elsewhere in the world
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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