125,872 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
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
'Gringos' in Mexico: Cross-sectional and longitudinal effects of language school-promoted contact on intergroup bias.
No full textAbstract: A longitudinal field study examined Pettigrew's (1998) intergroup contact theory and Gaertner et al.'s (2000) Common Ingroup Identity Model (CIIM). In Pettigrew's model, the contact-prejudice relation is mediated by changing behavior, ingroup reappraisal, generating affective ties, and learning about the outgroup. Pettigrew's integration of the three chief models of contact generalization into a time-sequence holds that contact first elicits decategorization, then salient categorization, and finally recategorization. In CIIM, these three levels of categorization-plus a fourth, dual identity-are thought to be mediators in the contact-prejudice relation. Results underline the crucial mediating role of behavior modification in Pettigrew's model and interpersonal and superordinate levels in CIIM. An attempt to partially integrate the two models is presented
Photograph - Mrs. G. F. Eller and Mayor Joseph L. Reid
No full textA photograph of Mary I. Eller and Mayor Joseph L. Reid. The reverse reads: "St. Catharines, Ontario - November 5th, 1976 Presentation, by Mrs. G. F. Eller, President of The Women's Literary Club of St. Catharines, of 'The First Eighty years' the clubs' history booklet, compiled by Mrs. G.M. Armstrong, Honorary President and Archivist, assisted by Miss Kathleen Duff, Assistant Archivist; to His Worship Mayor Joseph L. Reid, as our Centennial gift to the City of St. Catharines.
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
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
Minimum Fe requirement and toxic tissue concentration of Fe in Phragmites australis : A tool for alleviating Fe-deficiency in constructed wetlands
No full textIn constructed wetlands (CWs) with forced aeration and vertical flow, plants can suffer from iron (Fe) deficiency due to Fe immobilization in the gravel substrate as a consequence of the oxic condition. The common reed (Phragmites australis) is the most commonly used plant species in CWs and frequently displays Fe-deficiency symptoms particularly in new-established systems. The aim of this study was therefore to study the Fe-nutrition of P. australis in order to gain knowledge on how Fe-deficiency in P. australis can be alleviated. For this purpose, we grew two genetically distinct phylogeographic groups of P. australis hydroponically with seven different Fe concentrations (0, 0.1, 0.2, 0.5, 1.0, 5.0 and 20.0 mg Fe-EDDHA ([iron (3+) ethylenediamine di (o-hydroxyphenylacetic) acid]) L−1) in a phytotron. Both groups responded strongly to the increasing Fe supply. The belowground biomass allocation ratio, light-saturated photosynthesis rates, chlorophyll content and leaf Fe tissue concentration all significantly increased with increasing Fe availability. Phragmites australis in the 0 mg Fe-EDDHA L−1 treatment suffered strongly from Fe deficiency, and plants in the high 20.0 mg Fe-EDDHA L−1 treatment also had reduced growth and Fe toxicity symptoms. The ‘critical deficiency concentration’ of Fe in leaves of juvenile P. australis was 40–50 mg kg−1 DM, and the ‘critical toxicity concentration’ of Fe in leaves of juvenile P. australis were approximately 150 mg kg−1 DM. Overall the two genetically distinct P. australis groups differed in their ecophysiological traits, and the two groups also responded differently to the different Fe-supply rates which may be the result of adaptations obtained in their native growth habitats. We suggest that the Fe-deficiency in CW systems with unsaturated vertical flow and/or forced aeration can be alleviated by application of a foliar spray containing chelated iron. However, the application rate and frequency should be further studied
Safe Online Mobile Network Optimization Through Digital Twin-Enhanced Monte Carlo Tree Search
No full textThe efficient operation of cellular networks requires precise tuning of configuration parameters such as the antenna downtilt or the transmit power. Data-driven methods, which can integrate feedback from monitoring data, are promising but face challenges related to sample efficiency, scalability, and safety, limiting their real-world application. In this work, we introduce an innovative online coverage and capacity optimization framework that combines model-free exploration using Monte Carlo tree search with a safe, model-based baseline derived from a probabilistic differentiable network twin. We formulate the optimization task as a sequential tree search problem, developing specialized policies to guide the exploration of the configuration space. The differentiable network twin aids both the selection policy, by pruning the search space with a prior action distribution, and the rollout policy, enabling domain knowledge-based selection of remaining actions. Our results demonstrate that the proposed approach effectively guides the optimization process, outperforming both purely model-free and model-based methods. Our solution improves safety by reducing the risk of testing poorly performing configurations, enhances the model-based solution, and can also compensate for severe model mismatches in the digital twin. The framework thus addresses a common obstacle in applying data-driven optimization to real-world network deployments
Interactive effects of elevated temperature and CO2 on two phylogeographically distinct clones of common reed (Phragmites australis)
No full textThe aboveground growth, physiological and biochemical parameters of two clones of the cosmopolitan wetland grass Phragmites australis, grown at four treatment combinations of temperature and O2, were investigated to elucidate whether their climate response differed due to inherent differences in their ecological adaptation. The two phylogeographically distinct P. australis clones (DK clone, European genetic background; ALG clone, Mediterranean genetic background) were grown for 151 days in phytotrons at 19/12 8C (day/night temperature) and 390 ppm CO2, and at elevated temperature (+5 8C) and CO2 (700 ppm) with treatment factors alone or in combination.
The ALG clone had 2–4 times higher aboveground biomass, higher light-saturated rates of photosynthesis (Pmax), maximum electron transport rates (ETRmax) and Rubisco activity, and higher photosynthetic nitrogen-use efficiency than the DK clone. The DK clone, however, produced more shoots, leaves and sideshoots, and had 9–51 % higher specific leaf area and 15–39 % higher leaf nitrogen concentration than the ALG clone. Although elevated atmospheric CO2 alone barely affected the aboveground growth of the two P. australis clones, simultaneously elevated temperature and CO2 stimulated growth and aboveground biomass. Overall, elevated CO2 stimulated photosynthesis, but the clones responded differently to a concomitant increase in CO2 and temperature, depending on the phylogeographic background of the plant. The DK clone showed overall stronger responses, and can be considered the more plastic of the two clones with respect to CO2 and
temperature. Thus, the DK clone may be better adapted to climate change than the ALG clone, at least in the short term
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