1,721,165 research outputs found
Soil and microbial nutrient status are heterogeneous within an elevational belt on a neotropical mountain
No full textRoot quality and decomposition environment, but not tree species richness, drive root decomposition in tropical forests
No full textBackground and aims Tropical forests contribute significantly to the global carbon cycle, yet the relative importance of tree diversity on key ecosystem processes such as root decomposition remains unknown. Methods We examined the influence of tree species richness on root decomposition over 485 days at two sites in Panama with contrasting soil fertility. Diversity effects on decomposition rates were calculated where 1) overstory tree species richness and composition matched that occurring inside root decomposition bags and 2) where roots of contrasting species richness decomposed under a common tree overstory. In addition, we tested 27 root traits to identify those that contribute to predict root decomposition in tropical forests. Results Tree species richness did not affect root decomposition rates, neither when species were manipulated within bags nor with varying tree overstory richness. Root carbon quality and micronutrient concentrations such as manganese explained 47 and 81 % of the variation in decomposition rates in the fertile and infertile site, respectively, demonstrating that the relative importance of traits was modulated by the soil environment. Conclusions Our results suggest that root decomposition in tropical forests is mediated by root functional composition and the soil environment rather than by species richness
Soil Health Under Global Change and Human Impact
No full textABSTRACT Soil health is pivotal to sustain biological productivity, maintain environmental quality, and ensure the health of plants, animals, and ultimately humans. Global changes—such as climate warming, elevated CO₂ atmospheric concentration, droughts, and floods—as well as human impacts like land‐use change, chemical contamination, and application of fertilizer and pesticides, threaten soil health. Protecting soil health and raising global awareness on this topic are now critical to ensure sustainable management of natural and agricultural ecosystems under global change. This Special Issue includes 19 studies in three thematic groups. The first group includes methodological advances in the assessment of soil health, exploring new tools, techniques, and approaches for accurate evaluation. The second group encompasses studies examining how soil health responds to land‐use change, agricultural and forestry practices. The third group addresses human‐induced pollution and its effects on soil health. Overall, these studies provide contemporary insight into soil health in managed and natural ecosystems and methods for soil health evaluation. These contributions will shape strategies to sustain soil functions and preserve healthy soils for future generations, including efforts to meet Sustainable Development Goals for the 21st century.National Natural Science Foundation of China https://doi.org/10.13039/50110000180
Turner, Benjamin L.
No full textSee entry in Choctaw County, volume 2, page 25: https://digital.archives.alabama.gov/digital/collection/voter1867/id/67
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
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