1,720,954 research outputs found
Engineering Fire-Resilient Forests: Applications of Satellite Remote Sensing To Assess Aspen’s Distribution and Potential To Reduce Fire Hazard
Get PDFAcross the United States and globally, wildfire impacts to the built environment and ecosystems are driving increasing costs to society. There is no “one-size-fits-all” solution to reducing wildfire hazard for communities. The convergence of climate- and human-driven changes in wildfire activity requires collective action, innovative science and technology, and intentional management to mitigate the fire hazard. Addressing where and how we build, increasing wildland fire use and prescribed burning, and targeted fuels mitigation in hazard hotspots all play a significant role. However, traditional fuel treatments such as thinning or clear cutting often require revisitation to maintain positive benefits, creating persistent management challenges for communities. The expansion of “fire-resistant” species, such as quaking aspen (Populus tremuloides Michx.), has been proposed as one potential solution (or another “tool in the toolbox”) to reducing fire hazard in some regions, particularly in the Southern Rockies. Beyond the potential for aspen to reduce fire hazard, its ability to respond readily in post-disturbance landscapes provides critical forest resilience at a time when that has become more challenging due to compound disturbance interactions, a more fire-conducive climate, and increased area burned at high severity. However, more information is needed to understand where, how, and when aspen might moderate fire behavior, especially in the context of recent extreme fire activity. The growing widespread availability of remote sensing and geospatial data before, during, and after wildfires offers a promising avenue for elucidating answers to these questions and informing management decisions for this important forest species.
In this dissertation, I present a series of studies which leverage remote sensing and geospatial analysis, environmental data science, statistical and machine learning and ecological principles to explore one potentially novel solution to wildfire hazard: the management of quaking aspen as a living fire break. To this end, we first developed new reproducible methods for mapping aspen at a higher spatial resolution than existing products, identifying an average patch size of 0.53 ha in the Southern Rockies. These new maps have major implications for management decision-making, as small patches may be disproportionally important for both maintaining and expanding existing aspen stands. Next, we demonstrate a novel application of satellite-derive fire radiative power (FRP) harmonized with burn severity, national wall-to-wall forest inventory, and geographic setting to elucidate the relationship between aspen forest composition and structure on fire intensity and severity in the Southern Rockies. We found that the proportion of forested area that is made up of aspen has a significant influence on both intensity and severity, with a -8.1% reduction for every unit increase in proportional aspen area. Further, we found that the influence of aspen dominance diminishes greatly under more extreme fire weather but may still offer a buffering effect where it co-occurs with other forest types, especially lodgepole. This demonstrates the capacity for aspen forests, especially in greater proportions, to reduce extreme fire behavior in some settings. Finally, we harmonized a suite of environmental data to map and prioritize firesheds in the Southern Rockies based on archetypes of aspen management now and into the future. This exercise identified 93 (5.4%) firesheds where aspen management for fire hazard reduction may be advantageous and successful and provides a rich database geared towards management prioritization and planning. This overall effort contributes new data and ecological understanding of aspen’s distribution and potential to reduce fire hazard.</p
Engineering Fire-Resilient Forests: Applications of Satellite Remote Sensing To Assess Aspen’s Distribution and Potential To Reduce Fire Hazard
Get PDFAcross the United States and globally, wildfire impacts to the built environment and ecosystems are driving increasing costs to society. There is no “one-size-fits-all” solution to reducing wildfire hazard for communities. The convergence of climate- and human-driven changes in wildfire activity requires collective action, innovative science and technology, and intentional management to mitigate the fire hazard. Addressing where and how we build, increasing wildland fire use and prescribed burning, and targeted fuels mitigation in hazard hotspots all play a significant role. However, traditional fuel treatments such as thinning or clear cutting often require revisitation to maintain positive benefits, creating persistent management challenges for communities. The expansion of “fire-resistant” species, such as quaking aspen (Populus tremuloides Michx.), has been proposed as one potential solution (or another “tool in the toolbox”) to reducing fire hazard in some regions, particularly in the Southern Rockies. Beyond the potential for aspen to reduce fire hazard, its ability to respond readily in post-disturbance landscapes provides critical forest resilience at a time when that has become more challenging due to compound disturbance interactions, a more fire-conducive climate, and increased area burned at high severity. However, more information is needed to understand where, how, and when aspen might moderate fire behavior, especially in the context of recent extreme fire activity. The growing widespread availability of remote sensing and geospatial data before, during, and after wildfires offers a promising avenue for elucidating answers to these questions and informing management decisions for this important forest species.
In this dissertation, I present a series of studies which leverage remote sensing and geospatial analysis, environmental data science, statistical and machine learning and ecological principles to explore one potentially novel solution to wildfire hazard: the management of quaking aspen as a living fire break. To this end, we first developed new reproducible methods for mapping aspen at a higher spatial resolution than existing products, identifying an average patch size of 0.53 ha in the Southern Rockies. These new maps have major implications for management decision-making, as small patches may be disproportionally important for both maintaining and expanding existing aspen stands. Next, we demonstrate a novel application of satellite-derive fire radiative power (FRP) harmonized with burn severity, national wall-to-wall forest inventory, and geographic setting to elucidate the relationship between aspen forest composition and structure on fire intensity and severity in the Southern Rockies. We found that the proportion of forested area that is made up of aspen has a significant influence on both intensity and severity, with a -8.1% reduction for every unit increase in proportional aspen area. Further, we found that the influence of aspen dominance diminishes greatly under more extreme fire weather but may still offer a buffering effect where it co-occurs with other forest types, especially lodgepole. This demonstrates the capacity for aspen forests, especially in greater proportions, to reduce extreme fire behavior in some settings. Finally, we harmonized a suite of environmental data to map and prioritize firesheds in the Southern Rockies based on archetypes of aspen management now and into the future. This exercise identified 93 (5.4%) firesheds where aspen management for fire hazard reduction may be advantageous and successful and provides a rich database geared towards management prioritization and planning. This overall effort contributes new data and ecological understanding of aspen’s distribution and potential to reduce fire hazard.</p
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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