1,720,968 research outputs found
LWFBrook90.jl—Including Stable Water Isotopes in a Soil Vegetation Atmosphere Transport Model to Constrain Vertical Root Water Uptake Dynamics
No full textAbstract In water‐limited ecosystems, soil water availability plays a pivotal role in determining the stress levels experienced by vegetation. Understanding the vertical distribution of roots and root water uptake (RWU) is essential for accurately predicting drought conditions using Soil Vegetation Atmosphere Transport (SVAT) models. However, quantifying RWU in environments poses a considerable challenge. Here, stable isotope signatures in water offer a promising avenue for inferring RWU. They can effectively trace the movement of precipitation through soil layers into trees. Combining isotopes with precipitation and soil moisture content enables inferring relative and absolute contributions of soil layers to RWU, thereby providing added benefit over mixing models. In this study, we extended the SVAT model LWF‐Brook90 with transport of stable isotopes in water. The model was validated using measurements from a forest monitoring site and further test cases. Across calibration scenarios combining observed hydrometric and isotopic state variables as calibration targets, we compared model accuracy, predictive uncertainty, and parameter equifinality. Our results demonstrated that the model accurately reproduced observations and that overall model accuracy and precision could be improved by a multi‐objective calibration approach combining isotopic and hydrometric time series. Isotopes specifically constrained parameters linked to RWU and preferential infiltration. Including isotopes reduced uncertainty in parameter estimates and model predictions and reduced parameter equifinality. Combining isotope mixing with SVAT models holds the potential to significantly enhance our mechanistic understanding of water fluxes in water‐limited ecosystems, including dynamics of root water uptake, facilitating more accurate predictions of vegetation responses to changing environmental conditions.Plain Language Summary For vegetation relying on soil‐stored water, the depth of the root water uptake is critical during conditions with dry topsoil. In order to predict vegetation stress during drought with simulation models we need to understand at which depth the water a plant uses was taken up. However, measuring root water uptake is difficult. Often stable isotopes in water are used to track relative contribution of rainfall events or of soil layers to plant water. When we combine isotopic with soil moisture measurements, absolute contribution can be inferred. To do so, we extended the existing simulation model LWF‐Brook90 to enable calibrating the model to isotopic observations. This new implementation was validated, by calibrating it to observed data from a forest monitoring site as well as quantifying how well it fits and how uncertain its predictions are. We found that model uncertainty in parameters and predictions was reduced when using isotopes in addition to soil moisture and soil matric potential. From the combination of these observations, we can potentially infer more about the mechanistic working of the water fluxes in ecosystems than with either one of them. This is especially important if conditions shift due to climate change.Key Points We extend the process‐based, 1‐dimensional Soil Vegetation Atmosphere Transport model LWF‐Brook90 with transport of stable isotopes in water The model is successfully validated against hydrometric as well as soil and xylem water isotope observations from a forest monitoring site Calibrating 55 model parameters with isotopes reduces predictive uncertainty and parameter equifinality, especially for soil water fluxesAbstract In water‐limited ecosystems, soil water availability plays a pivotal role in determining the stress levels experienced by vegetation. Understanding the vertical distribution of roots and root water uptake (RWU) is essential for accurately predicting drought conditions using Soil Vegetation Atmosphere Transport (SVAT) models. However, quantifying RWU in environments poses a considerable challenge. Here, stable isotope signatures in water offer a promising avenue for inferring RWU. They can effectively trace the movement of precipitation through soil layers into trees. Combining isotopes with precipitation and soil moisture content enables inferring relative and absolute contributions of soil layers to RWU, thereby providing added benefit over mixing models. In this study, we extended the SVAT model LWF‐Brook90 with transport of stable isotopes in water. The model was validated using measurements from a forest monitoring site and further test cases. Across calibration scenarios combining observed hydrometric and isotopic state variables as calibration targets, we compared model accuracy, predictive uncertainty, and parameter equifinality. Our results demonstrated that the model accurately reproduced observations and that overall model accuracy and precision could be improved by a multi‐objective calibration approach combining isotopic and hydrometric time series. Isotopes specifically constrained parameters linked to RWU and preferential infiltration. Including isotopes reduced uncertainty in parameter estimates and model predictions and reduced parameter equifinality. Combining isotope mixing with SVAT models holds the potential to significantly enhance our mechanistic understanding of water fluxes in water‐limited ecosystems, including dynamics of root water uptake, facilitating more accurate predictions of vegetation responses to changing environmental conditions.Plain Language Summary For vegetation relying on soil‐stored water, the depth of the root water uptake is critical during conditions with dry topsoil. In order to predict vegetation stress during drought with simulation models we need to understand at which depth the water a plant uses was taken up. However, measuring root water uptake is difficult. Often stable isotopes in water are used to track relative contribution of rainfall events or of soil layers to plant water. When we combine isotopic with soil moisture measurements, absolute contribution can be inferred. To do so, we extended the existing simulation model LWF‐Brook90 to enable calibrating the model to isotopic observations. This new implementation was validated, by calibrating it to observed data from a forest monitoring site as well as quantifying how well it fits and how uncertain its predictions are. We found that model uncertainty in parameters and predictions was reduced when using isotopes in addition to soil moisture and soil matric potential. From the combination of these observations, we can potentially infer more about the mechanistic working of the water fluxes in ecosystems than with either one of them. This is especially important if conditions shift due to climate change.Key Points We extend the process‐based, 1‐dimensional Soil Vegetation Atmosphere Transport model LWF‐Brook90 with transport of stable isotopes in water The model is successfully validated against hydrometric as well as soil and xylem water isotope observations from a forest monitoring site Calibrating 55 model parameters with isotopes reduces predictive uncertainty and parameter equifinality, especially for soil water fluxesAbstract In water‐limited ecosystems, soil water availability plays a pivotal role in determining the stress levels experienced by vegetation. Understanding the vertical distribution of roots and root water uptake (RWU) is essential for accurately predicting drought conditions using Soil Vegetation Atmosphere Transport (SVAT) models. However, quantifying RWU in environments poses a considerable challenge. Here, stable isotope signatures in water offer a promising avenue for inferring RWU. They can effectively trace the movement of precipitation through soil layers into trees. Combining isotopes with precipitation and soil moisture content enables inferring relative and absolute contributions of soil layers to RWU, thereby providing added benefit over mixing models. In this study, we extended the SVAT model LWF‐Brook90 with transport of stable isotopes in water. The model was validated using measurements from a forest monitoring site and further test cases. Across calibration scenarios combining observed hydrometric and isotopic state variables as calibration targets, we compared model accuracy, predictive uncertainty, and parameter equifinality. Our results demonstrated that the model accurately reproduced observations and that overall model accuracy and precision could be improved by a multi‐objective calibration approach combining isotopic and hydrometric time series. Isotopes specifically constrained parameters linked to RWU and preferential infiltration. Including isotopes reduced uncertainty in parameter estimates and model predictions and reduced parameter equifinality. Combining isotope mixing with SVAT models holds the potential to significantly enhance our mechanistic understanding of water fluxes in water‐limited ecosystems, including dynamics of root water uptake, facilitating more accurate predictions of vegetation responses to changing environmental conditions.Plain Language Summary For vegetation relying on soil‐stored water, the depth of the root water uptake is critical during conditions with dry topsoil. In order to predict vegetation stress during drought with simulation models we need to understand at which depth the water a plant uses was taken up. However, measuring root water uptake is difficult. Often stable isotopes in water are used to track relative contribution of rainfall events or of soil layers to plant water. When we combine isotopic with soil moisture measurements, absolute contribution can be inferred. To do so, we extended the existing simulation model LWF‐Brook90 to enable calibrating the model to isotopic observations. This new implementation was validated, by calibrating it to observed data from a forest monitoring site as well as quantifying how well it fits and how uncertain its predictions are. We found that model uncertainty in parameters and predictions was reduced when using isotopes in addition to soil moisture and soil matric potential. From the combination of these observations, we can potentially infer more about the mechanistic working of the water fluxes in ecosystems than with either one of them. This is especially important if conditions shift due to climate change.Key Points We extend the process‐based, 1‐dimensional Soil Vegetation Atmosphere Transport model LWF‐Brook90 with transport of stable isotopes in water The model is successfully validated against hydrometric as well as soil and xylem water isotope observations from a forest monitoring site Calibrating 55 model parameters with isotopes reduces predictive uncertainty and parameter equifinality, especially for soil water fluxe
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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