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Chemotaxonomische Unterscheidung des Holzes von Swietenia macrophylla King aus Plantagen und Naturwaldbeständen
No full textChemotaxonomische Bestimmung von Holzarten und Herkünften in Zellstoff und Papier
No full textThis work presents the development and proof of concept of a novel chemical method for wood taxa and origin identification in pulp and paper. In order to conserve nature and halt the ongoing and severe crossings of planetary boundaries such as land-system change and biosphere integrity, it is essential to combat deforestation and the loss of genetic diversity within global forests. Therefore, a variety of national and international laws have been enacted with the objective of protecting the environment. However, there is a need for science-based monitoring tools to ensure that these laws are effectively enforced in practice.
The method is based on the differentiation of wood extract profiles that remain in pulp (chemotaxonomic fingerprinting) and involves cryo-ball mill grinding and Soxtherm extraction of bleached pulp or paper samples with n-hexane, followed by thermodesorption of the dried extracts and gas chromatography - mass spectrometry (TD-GC-MS) analysis. The generated chromatograms undergo a series of pre-processing steps, including ion filtering, smoothing and peak deconvolution and are then added to the reference database (DB). The investigation of optimal configuration settings for the DB was also part of this work. The subsequent identification of samples of unknown composition is conducted through querying against the DB on three comparison parameters: marker peak scores (MPS), reverse similarity index (RSI), and matched chromatogram area (MCA). The methodology has been validated on different measuring devices. However, there is currently a partial dependence of the database query results on the measuring system. Furthermore, the novel extractant-based approach was evaluated in an independent external blind test and compared to the established anatomical identification method. The blind test comprised 38 exemplary species of mainly tropical hardwood, which were processed in unknown mixtures into 15 test sheets and provided to four participating institutes for analysis. The results demonstrate that the new chemotaxonomic method yielded outcomes that were comparable to those obtained through the morphological-anatomical method, which is currently employed for all assessments. However, both approaches show distinct strengths and weaknesses in the recognition of individual wood taxa, suggesting that a combination of both methods could potentially enhance the overall hit rate.
Another study included in this work successfully differentiated the origins of the wood genera Gonystylus and Rubroshorea and the wood species Tectona grandis in fully bleached pulps. Certain compounds responsible for the differentiation of specific geographical origins were found for every taxon. The results of the origin differentiation could be particularly useful for the verification of harvest origin declarations at border crossings of pulp and paper products, as well as for the enforcement of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Currently, this is the only method available for this purpose. A variety of optimisation possibilities of the chemotaxonomic database approach are discussed, including sample preparation techniques such as advanced tuning of the GC-MS instruments used, data processing methods such as ion filter settings and database
configuration. The outlook section outlines future prospects for further method validation on industrial samples and the potential use of machine learning for automation
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
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