117,920 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Semi-continuous anaerobic digestion of mixed wastewater sludge with biochar addition
No full textThis work analysed the effects of Biochar (BC) addition to the Anaerobic digestion (AD) of wastewater Mixed sludge (MS) in semi-continuous mode. A 3 L digester was operated at 37 °C for 100 days, feeding MS collected every three weeks in the same wastewater treatment plant, and 10 g L−1 of BC. The average performance of MS digestion (biogas 188 NmL d−1, 68% methane) improved in presence of BC (biogas 244 NmL d−1, 69% methane). According to the results of the multiple linear regression analysis performed on the experimental data, the 79% variation of the soluble COD in the MS was the driving factor for the 38% increase of biogas and methane yields. In conclusion, in the considered experimental conditions, the variability of the substrate's composition was the key factor driving the performances of the AD of MS, independently of the addition of BC
Addition of different biochars as catalysts during the mesophilic anaerobic digestion of mixed wastewater sludge
No full textBiochar (BC) recently gained attention as an additive for anaerobic digestion (AD). This work aims at a critical analysis of the effect of six BCs, with different physical and chemical properties, on the AD of mixed wastewater sludge at 37 °C, comparing their influence on methane production and AD kinetics. AD batch tests were performed at the laboratory scale operating 48 reactors (0.25 L working volume) for 28 days with the addition of 10 g L−1 of BC. Most reactors supplemented with BCs exhibited higher (up to 22%) methane yields than the control reactors (0.15 Nm3 kgVS−1). The modified Gompertz model provided maximum methane production rate values, and in all reactors the lag-phase was equal to zero days, indicating a good adaptation of the inoculum to the substrate. The potential correlations between BCs’ properties and AD performance were assessed using principal component analysis (PCA). The PCA results showed a reasonable correlation between methane production and the BCs’ O–C and H–C molar ratios, and volatile matter, and between biogas production and BCs’ pore volume, specific surface area, and fixed and total carbon. In conclusion, the physic-chemical properties of BC (specifically, hydrophobicity and morphology) showed a key role in improving the AD of mixed wastewater sludge
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
Figs. 39–50 in Molecular phylogeny and classification of Lyropaeini (Coleoptera: Lycidae) with description of larvae and new species of Lyropaeus
No full textFigs. 39–50. Male genitalia of Lyropaeus (Lyroneces): 39, L. dominator Kleine; 40, L. humeralis Kleine; 41, L. monticola Kleine; 42, L. optabilis Kleine; 43, L. philippinensis Kleine; 44, L. ritsemae Gorham; 45, L. rubrostriatus Kleine; 46, L. waterhousei Gorham. Mouth parts of L. (Lyroneces) optabilis: 47, labium; 48, maxillary palpus; 49, mandible. Pronotum: 50, L. (Lyroneces) optabilis. Scale bars = 0.25 mm (Figs. 39–46, 47–49); scale bar = 0.5 mm (Fig. 50).Published as part of Masek, Michal, Ivie, Michael A., Palata, Vaclav & Bocak, Ladislav, 2014, Molecular phylogeny and classification of Lyropaeini (Coleoptera: Lycidae) with description of larvae and new species of Lyropaeus, pp. 136-145 in Raffles Bulletin of Zoology 62 on page 142, DOI: 10.5281/zenodo.535356
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
Analysis of the influence of activated biochar properties on methane production from anaerobic digestion of waste activated sludge
No full textThis work describes the impacts of biochar (BC) addition to the anaerobic digestion (AD) of waste activated sludge (WAS). Three BCs, produced by pyrolysis at 550 °C of different waste biomasses (soft wood, sewage sludge and rice husk), then physically activated at 900 °C with CO2, were investigated as additives. AD tests were performed in batch mode at 37 °C, feeding 2% total solids and 10 g L−1 BC. While none of the considered BCs increased biogas yield compared to control digesters, the activated BCs with higher surface area, porosity and hydrophobicity (RH550a from rice husk and SS550a from sewage sludge) boosted methane yield (up to 105% for RH550a). The experimental methane production were: 0.037 Nm3 kgVS−1 for SWP550a, 0.081 Nm3 kgVS−1 for SS550a, 0.142 Nm3 kgVS−1 for RH550a and 0.069 Nm3 kgVS−1 for control reactors. CO2 adsorption (3.14 mmol g−1 for RH550a, 0.97 mmol g−1 SS550a) calculated from experimental data was consistent with literature (0.4–2.3 mmol g−1 BC). The fitting of experimental methane productions through the modified Gompertz equation showed an acceleration of methane production for all BCs, with a reduction of the lag phase compared to control reactors (0.5 days vs 2.6 days). This work, although confirming literature data about CO2 adsorption, brings new insights on the influence of specific physico-chemical properties of BC as additive in AD of WAS. Surface area, porosity, hydrophobicity and alkali and alkaline metals content in ashes were the most important BC properties affecting AD of activated sewage sludge
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
On the Use of Actinometric Emission Spectroscopy in SF6-O2 Discharges: Theoretical and Experimental Analysis
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