1,720,956 research outputs found
Intraspecific variability of leaf traits and functional strategy of Himantoglossum adriaticum H. Baumann
Get PDFTrait-based studies have become extremely common in plant ecology. In this work we analysed intraspecific trait variation of Himantoglossum adriaticum, a European endemic orchid species of Community interest, to investigate whether different populations growing on managed and abandoned semi-natural dry grasslands show differences in the CSR strategy. In seven populations occurring in Veneto Region (NE Italy), we measured H. adriaticum maximum vegetative height, leaf traits (LA, LDMC, SLA) and calculated the CSR strategy. Through CCA we investigated the relationship between plant traits and both plant community attributes (cover and height of herbs and shrubs), and geomorphologic features (aspects and slope). PERMANOVA test was used to investigate if the CSR strategy of H. adriaticum varied according to the management regime. Results showed that individuals of H. adriaticum develop different strategies when growing in different habitats. Specifically, individuals growing in managed fully sunny dry grasslands reached higher vegetative height (MH), had lower values of SLA and a higher relative contribution of the C parameter than individuals growing in abandoned dry grasslands, which, on the contrary, were shorter, had higher values of SLA (and correspondingly lower values of LDMC) and a higher relative contribution of the R parameter. Further data on reproductive traits (e.g. fruit and seed-set) may corroborate our results. Although the number of individuals addressed in this study is rather low, and our conclusions may not be considered of general validity for the species, our study demonstrated the applicability of the CSR strategy scheme in detecting functional strategies at intraspecific level
Organic proxies in speleothems: analytical method and first data from cave KNI-51
Get PDFSpeleothems are important archives for paleo environments thanks to their high temporal resolution and potential for precise and accurate dating. Organic biomarkers in speleothems are not widely explored because of low concentrations and high sample amount required to obtain detectable levels. The potential for paleoenvironmental reconstruction from organic molecules in speleothems is high, but low contamination and high sensitivity analytical tools are required to obtain well resolved and reliable records. We developed a method for the analysis of fire-derived polycyclic aromatic hydrocarbons (PAHs) and nalkanes in speleothems and applied it to aragonite stalagmites from cave KNI-51 in the central Australian tropics. These stalagmites have already been precisely dated by U/Th methods, and have detailed oxygen isotopic time series that provide a detailed record of past Australian monsoon rainfall variability [1]. The characteristics of the cave make it suitable for this research, thanks to the considerably high growth rates of the stalagmites (1-2 mm yr-1), that allow analysis at an annual resolution. In addition, cave KNI-51 is shallow, contained within highly permeable rillenkarren limestone, and overlain by extremely thin, carbon-poor soils. Thus, the sequestration, biodegradation, or mobilization of PAHs and n-alkanes in soils and bedrock are minimized, allowing them to be easily transported from the surface to the stalagmite. In order to check for the risk of contamination of the aragonite layers during flooding episodes, we also analyzed sediments from above and inside the cave. Results show that flood sediments do not bias our analyses of carbonate material. With respect to the few existing methods for PAH analysis in speleothems [2, 3], some substantial modifications were made to the pre-analytical phase, all of which were aimed at increasing the analytical signal: our analytical protocol allows detection of analytes in stalagmites at the ng to sub-ng level by guaranteeing the lowest contamination. Samples are drilled from pre-cleaned stalagmite slabs, dissolved in HCl at low temperature, solvent-extracted and volume reduced in a class 10,000 organic cleanroom. 19 different 2- to 6-ring PAH compounds and 26 n-alkanes (C10-C35) were analyzed and quantified by GC-MS. Preliminary results suggest increased fire activity in the mid-15thcentury, marked in particular by the presence of fluoranthene, pyrene, benzo(e)pyrene and indeno(1,2,3-c,d)pyrene. Only high molecular weight n-alkanes in the range C23-C32 had significant concentrations in most samples, showing no marked odd-even predominance, likely indicating the presence of another source beside plant residues in soil
Are food-deceptive orchid species really functionally specialized for pollinators?
Get PDFFood-deceptive orchid species have traditionally been considered pollination specialized to bees or butterflies. However, it is unclear to which concept of specialization this assumption is related; if to that of phenotypic specialization or of functional specialization. The main aim of this work was to verify if pollinators of five widespread food-deceptive orchid species (Anacamptis morio (L.) R.M. Bateman, Pridgeon & M.W. Chase, Anacamptis pyramidalis (L.) Rich., Himantoglossum adriaticum H. Baumann, Orchis purpurea Huds. and Orchis simia Lam.) predicted from the phenotypic point of view matched with the observed ones. We addressed the question by defining target orchids phenotypic specialization on the basis of their floral traits, and we compared the expected guilds of pollinators with the observed ones. Target orchid pollinators were collected by conducting a meta-analysis of the available literature and adding unpublished field observations, carried out in temperate dry grasslands in NE Italy. Pollinator species were subsequently grouped into guilds and differences in the guild spectra among orchid species grouped according to their phenotype were tested. In contradiction to expectations derived from the phenotypic point of view, food-deceptive orchid species were found to be highly functionally generalized for pollinators, and no differences in the pollinator guild spectra could be revealed among orchid groups. Our results may lead to reconsider food-deceptive orchid pollination ecology by revaluating the traditional equation orchid-pollination specialization
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
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