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Assessing nutrient responses and biomass quality for selection of appropriate paludiculture crops
No full textTall wetland graminoids with rapid growth, high productivity and wide tolerance of biotic and abiotic stresses are
potentially valuable bioenergy crops, especially when grown in rewetted peat soils for biomass (paludiculture).
Using wetland plants as renewable bioenergy crops instead of fossil fuels has the ecological benefits of reducing
greenhouse gas (GHG) emissions, improving water quality and conserving peat soils. As these potential crops will
grow in peat that differs in nutrient availability, not only will their biomass productivity be affected, but also the
biomass quality for bioenergy may be altered. We set up five different nutrient availability treatments in waterlogged peat soil to simulate different nutrient environments for wetland plant cultivation. Seven wetland plants
suitable for paludiculture (Typha latifolia, Arundo plinii, Arundo donax and four distinct genotypes of Phragmites
australis from Denmark, The Netherlands, Romania and Italy) were selected to test responses of biomass production and tissue quality to different nutrient availability. Due to their high biomass productivity, T. latifolia,
A. donax, Dutch (NL) and Romanian (RO) P. australis had the greatest potential to produce bioenergy feedstock.
All taxa survived when cultivated with very low nutrient availability, especially NL and RO P. australis and
T. latifolia. Moreover, biomass quality was both species-specific and element-specific, affected by increasing nutrient availability. Overall, T. latifolia had the lowest tissue concentrations of S and Si as well as high concentrations of Ca, and therefore the best tissue quality for combustion both at low and high nutrient availability.
These results will provide crucial information for choosing appropriate crops and managements and promote
the success of culturing wetland plants as bioenergy feedstock
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
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
Intraspecific variation in Phragmites australis: Clinal adaption of functional traits and phenotypic plasticity vary with latitude of origin
No full text1. Widespread plant species generally have high intraspecific variation in functional traits, which is reflected in their great variety of phenotypes. This variety can result from both genetic differences due to local adaptation and phenotypic plasticity. With high intraspecific variation and nearly global distribution, the common reed Phragmites australis is a suitable model species for studying the underlying mechanisms of intraspecific trait variation.
2. In this study, 71 genotypes of P. australis from seven phylogeographic groups were transplanted into two replicate common gardens located in very different climates: northern Europe and mid‐east Asia. We measured seven functional traits of all these genotypes over the growing season, including shoot height, maximum biomass per shoot, shoot density, node number per stem, leaf life span, flowering occurrence and flowering date. Our aim was to assess the relative effects of genetic (phylogeographic origin) and environmental (common garden) status, and interactions between them, on intraspecific variation in functional traits of P. australis.
3. We found common garden having the strongest influence on most functional traits studied. All traits except flowering occurrence varied significantly across gardens, revealing the important role of phenotypic plasticity on trait variation in P. australis. We also found significant differences in trait variation among the different phylogeographic groups of P. australis and, thus, evidence for genetically determined intraspecific variation in the morphological and life‐history traits addressed in this study. All functional traits showed significant (p ≤ 0.0054), albeit minor to moderately explained (R2 ≤ 0.57), latitudinal patterns in both gardens. Covariation of multiple traits was similar in the two gardens. Phenotypic plasticity was trait‐ specific, and the plasticity of shoot height and maximum biomass per shoot increased towards higher latitude of genotypic origin. Our results indicate that the latitude of origin affects the evolution of functional traits, as well as their phenotypic plasticity.
4. Since phenotypic plasticity is a crucial mechanism for acclimation and evolution, our findings support the role of gene‐based adaptive phenotypic plasticity in plant evolution. The intraspecific spatial variation in functional traits and their phenotypic plasticity can help predict species distribution, persistence and invasion under global climate change
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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