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Interactions between metal and drought stressors on plant water relationships and their effects at ecosystem level
Get PDFHeavy metals influence plant traits that are relevant to its internal water status.
Therefore, knowledge of metal effects on a plant’s ability to tolerate other stresses such
as drought is important to ensure sustainability of restoration efforts in contaminated
landscapes, often prone to drought. The aim of this thesis was to gain understanding how
heavy metal contamination influences plant-water relationships and how this interacts
with effects of a simultaneous drought. Levels ranging from organs to ecosystem
processes were investigated. Chapter 1 briefly reviews published studies on interactions
between metal and drought stress and highlights potential gaps in literature. Chapter 2
presents results of a 2-year outdoor lysimeter study on the effects of Cu-Ni toxicity on
plant-water relationships using saplings of Acer rubrum, Betula papyrifera, and Quercus
rubra. The study shows that under elevated metal levels the plants use less water but suffer
drought symptoms even if there is water available. Chapter 3 investigates, using B.
papyrifera, whether such metal effects on water use are a result of short-term exposure of
roots on their water uptake capacity, or due to long-term structural damage e.g. on
hydraulic architecture. Both effects were found, but were smaller than hypothesized. In
Chapter 4 influence of metals on plant’s vulnerability to xylem embolisms in Acer
rubrum saplings is found to be higher in the metal contaminated region of Sudbury,
Ontario, compared to surrounding uncontaminated regions. Chapter 5 establishes
guidelines and limitations for transporting leaves from field to laboratory when
measuring leaf relative water content, a method that is important for studying plant water
relations in the field. Finally, I conclude with a general overall summary of results and
proposed suggestions for reclamation projects
Reliability of leaf relative water content (RWC) measurements after storage: consequences for in situ measurements
Get PDFRelative Water Content (RWC) is widely used to describe plant water status, and is commonly measured gravimetrically. The ephemeral nature of leaf fresh mass poses severe constraints for such measurements in field-grown plants. These constraints can be overcome by transporting the leaves in waterproof containers into the lab. However, even then leaves lose water, and other changes may happen. The effects of a delay on the measurement of RWC have not been quantified so far. In this study the influence of duration of storage up to 96 hours and storage temperature on RWC and its components was investigated for four species. Alnus incana, Impatiens capensis, Scirpus microcarpus leaves were stored in plastic bags, those of Comptonia peregrina in plastic vials. RWC remained within 5% of the initial value during 24 h cool storage, but after that larger changes were observed. The effects of storage were species specific, being most pronounced in species poorly protected against desiccation, and under warm conditions. The effects of storage were not only limited to water loss, but also included cellular degradation. In general, storage at 10 °C for 24 h enables measurement of RWC for field-grown plants with accuracy of a few percent, but care has to be taken with species vulnerable to desiccation, possibly requiring faster measurement and a cooler storage temperature.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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