1,720,981 research outputs found
The effect of secondary metabolites, nutrients and invertebrates on fungal establishment and decomposition rates in European Aspen (Populus tremula)
No full textFungal decomposer communities play an essential role in nutrient cycling and are one of the main drivers of decomposition. Although fungal community composition has been seen to influence the rate of wood decay, little is known about the influence of invertebrates and secondary metabolites on the activity and composition of fungal decomposers. Studies have found that the exclusion of invertebrates from newly dead trees decrease decomposition rates in deadwood. Still, studies investigating if this is persistent through time are lacking. Therefore, the aim of this study was to investigate the influence of secondary metabolites, nutrients and invertebrates on fungal community composition and decomposition rates in Populus tremula.
Considering that our study was a follow-up, we analyzed wood and bark samples taken at the onset of the previous study to investigate the relationship between initial nutrients, secondary metabolites and fungal communities. This was then linked to fungal OTU (operational taxonomic unit) data from the previous study. To investigate if the effect of initial invertebrate exclusion on wood decomposition was maintained through time, we resampled 120 logs distributed between 30 sites for new density measurements. In addition, the number of polypore fruit bodies was recorded on all 120 logs to see if the number of polypore fruit bodies could reflect the degree of wood decay in logs.
We found that initial secondary metabolites and nutrients in individual trees significantly explained some variation in fungal community composition. Wood and bark chemistry also varied noticeably between individual trees of P. tremula, suggesting that individual trees can have divergent effects on decomposer communities. Although the initial invertebrate exclusion did not significantly affect wood decomposition five years after tree death, we still observed a trend in wood density similar to that of the previous study. We found that logs with many polypore fruit bodies had a significantly lower wood density than logs with none. This suggests that the presence of many polypore fruit bodies might indicate a greater density loss.
This study, along with the previous experimental study, strongly suggests that invertebrate exclusion along with initial wood and bark chemistry in P. tremula indirectly affect decomposition of dead wood through directly affecting establishment of fungal decomposer communities. Still, long term studies are needed to further understand the effect of invertebrates and initial wood and bark chemistry on fungi and wood decay
Effekten av sekundære metabolitter, næringsstoffer og invertebrater på etablering av sopp og nedbrytningsrate I Osp (Populus tremula)
Full text linkFungal decomposer communities play an essential role in nutrient cycling and are one of the main drivers of decomposition. Although fungal community composition has been seen to influence the rate of wood decay, little is known about the influence of invertebrates and secondary metabolites on the activity and composition of fungal decomposers. Studies have found that the exclusion of invertebrates from newly dead trees decrease decomposition rates in deadwood. Still, studies investigating if this is persistent through time are lacking. Therefore, the aim of this study was to investigate the influence of secondary metabolites, nutrients and invertebrates on fungal community composition and decomposition rates in Populus tremula.
Considering that our study was a follow-up, we analyzed wood and bark samples taken at the onset of the previous study to investigate the relationship between initial nutrients, secondary metabolites and fungal communities. This was then linked to fungal OTU (operational taxonomic unit) data from the previous study. To investigate if the effect of initial invertebrate exclusion on wood decomposition was maintained through time, we resampled 120 logs distributed between 30 sites for new density measurements. In addition, the number of polypore fruit bodies was recorded on all 120 logs to see if the number of polypore fruit bodies could reflect the degree of wood decay in logs.
We found that initial secondary metabolites and nutrients in individual trees significantly explained some variation in fungal community composition. Wood and bark chemistry also varied noticeably between individual trees of P. tremula, suggesting that individual trees can have divergent effects on decomposer communities. Although the initial invertebrate exclusion did not significantly affect wood decomposition five years after tree death, we still observed a trend in wood density similar to that of the previous study. We found that logs with many polypore fruit bodies had a significantly lower wood density than logs with none. This suggests that the presence of many polypore fruit bodies might indicate a greater density loss.
This study, along with the previous experimental study, strongly suggests that invertebrate exclusion along with initial wood and bark chemistry in P. tremula indirectly affect decomposition of dead wood through directly affecting establishment of fungal decomposer communities. Still, long term studies are needed to further understand the effect of invertebrates and initial wood and bark chemistry on fungi and wood decay.M-LU
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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