1,721,044 research outputs found
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
Application of biochar to anaerobic digestion versus digestate: Effects on N emissions and C stability
No full textResearch attention is growing for biochar as amendment for anaerobic digestion (AD), as it may improve both the AD process and digestate properties. In this study, two biochars (from insect frass or the woody fraction of green waste, both pyrolyzed at 450 C) were added (5 % w/w) during semi-continuous AD of organic kitchen waste and chicken manure. Biochar was mixed either during the AD process or to the digestate post-treatment. The impact of biochar addition on the AD process, NH3 and greenhouse gas emissions, as well as C and N mineralization following soil application, was examined. Biochar did not affect the biogas yield, but did lead to a reduction in NH3 levels in the biogas and NH4+-N sorption onto the biochars, reducing the risk of AD inhibition. N sorbed as NH4+-N onto the biochar was more available for mineralization than N sorbed as NH3. N sorption on biocharamended digestates did not result in trade-offs when these digestates were applied to soil: the sorbed N was not released as NH3 or N2O after soil application and was not released as mineral N in either the short or medium term. The C-rich biochars increased the OC content of the digestate, which enhanced its value as soil improver. Additionally, mixing biochar with digestate decreased the soil CO2 emissions up to 33 % when it was added after AD; no priming effects were observed. These findings highlight the potential benefits of incorporating biochar into AD systems and the subsequent application of biochar-amended digestate in agricultural practices.Acknowledgements
Flanders Research Foundation (FWO) provided (co-)funding for this study (BASTA, S000119N). We thank Tom Van Gyseghem, Siebert Vierendeels, Koen Van Loo and the other ILVO lab technicians for their technical assistance. We thank Dr. Paul Quataert and Dr. Klaas Sys (ILVO) for their assistance with statistical analyses. We gratefully acknowledge Miriam Levenson (ILVO) for English-language editing
CO-PYROLYSIS OF WOOD AND CHICKEN MANURE FOR THE PRODUCTION OF ENGINEERED BIOCHAR-BASED SLOW-RELEASE FERTILIZERS
No full textCO-PYROLYSIS OF WOOD AND CHICKEN MANURE FOR THE PRODUCTION OF ENGINEERED BIOCHAR-BASED SLOW-RELEASE FERTILIZERS
No full textManure biochar as a potential promising adsorbent for Cd-polluted soil remediation
No full textThe Campine region in Flanders is well-known for its highly cadmium (Cd)-contaminated soils due to past anthropogenic activities. Enhanced Cd exposure can cause cellular damage in plants, and consequently reduces crop growth and plant quality (Jozefczak et al., 2014). Currently, few cost-effective and non-destructive remediation techniques exist (Tang and Ni, 2021). Therefore, alternative soil remediation techniques should be assessed. Biochar is a solid material that is produced by pyrolysis of biomass. Because of its functional surface, it can be used as a cost-effective adsorbent for various (in)organic pollutants in soils and waste waters (Sizmur et al., 2017). However, differences in biochar properties will affect their adsorption performance. Therefore, suitable biomass streams and biochar production conditions should be selected to increase adsorption efficiency. Biochars from eight biomass feedstocks (spent peat, green waste, chicken manure, coffee grounds, flax shives, insect frass, tree bark and apple wood) were subjected to pyrolysis at 450 and 600 °C (pilot-scale rotary kiln reactor) and evaluated for their Cd removal efficiency (CRE) in a buffered 2-(N-morpholino)ethanesulfonic acid (MES) solution (0.025 M Cd; pH = 6; 1:20 solid:liquid ratio) for ten days. The results show that CRE varied from 4 to 96 wt.% with the highest CRE by chicken manure biochars (94-96 wt.%). Insect frass biochar (produced at 450 °C) also had a high CRE (77 ± 4 wt.%). All the other biochars exhibited a CRE below 50 wt.%. A 10-day kinetic adsorption study in the MES solution was executed on four biochars (450 °C) (tree bark, spent peat, insect frass and chicken manure) due to their divergent adsorption performance. A 24-hr desorption step with 0.01 M Ca(NO3)2 was executed to investigate the leachability of the adsorbed Cd. Chicken manure biochar showed the fastest Cd removal rate with a removal of 93 ± 1 wt.% within one day, while the Cd removal of insect frass biochar started at 41 ± 2 wt.% and gradually increased to 77 ± 4 wt.%. Cd Leaching from the loaded biochar was limited (< 10 wt.%) but spent peat biochar leached approx. two times more Cd compared to chicken manure biochar. Future pot and large-scale plant growth experiments with these biochars will provide more insight on their performance in real-life scenarios. This will open new possibilities for the remediation of Cd-contaminated soils
Biochar amendment to cattle slurry reduces NH3 emissions during storage without risk of higher NH3 emissions after soil application of the solid fraction
No full textCattle slurry storage is a major source of gaseous N emissions. The aim of this study was to evaluate the effects of biochar, clinoptilolite and elemental sulfur (S°) on (1) NH3 and greenhouse gas emissions during storage of cattle slurry and (2) after soil application of the enriched solid fractions; and (3) on the agronomic quality of the solid and liquid fractions. In the first phase, biochar was added to the slurry (10 g L-1); subsequently in the second phase, clinoptilolite (50 g L-1), S° (1 g L-1) and 40 g L-1 extra biochar were added. Gaseous emissions were monitored by a semi-continuous multi-gas analyzer and the agronomic quality of solid and liquid fractions was assessed after separation. The enriched solid fractions were applied to soil to study the effects on gaseous emissions, N and C mineralization. Amendment of biochar reduced NH3 emissions during cattle slurry storage by 12% during the first 7 days. Extra amendment of biochar, clinoptilolite and S° in combination with biochar resulted in a decrease of NH3 emissions of approximately 20%. The N sorbed from the slurry by the biochar was not released as NH3 during soil application of the solid fractions and was not released as mineral N in the short term (within 28 days). A short-term positive priming effect of biochar on the C mineralization of manure and biochar-manure mixture applied to soil was observed. The biochar-enriched solid fractions contained more C, total and organic N and water-available P with a slow release.The Research Foundation - Flanders (FWO) has (co-)financed the research (BASTA, S000119N). We thank Tom Van Gyseghem, Siebert Vierendeels, Koen Van Loo and the other ILVO lab technicians for their technical assistance. We are grateful to Miriam Levenson (ILVO) for English-language editing
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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