1,720,964 research outputs found
Measured and estimated tree dimensions of maritime pine (Pinus pinaster) and birch (Betula pendula) in the tree diversity experiment ORPHEE at the end of 2014
No full textThe ORPHEE experiment is located 40km south of Bordeaux (44°440 N, 00° 460 W) and belongs to the worldwide Tree Diversity Network (TreeDivNet). The experimental plantation was established in January 2008 on a clear cut of former maritime pine stands on a sandy podzol. Eight blocks were established, with 32 plots in every block. Each plot contained 10 rows of 10 trees planted 2 m apart, resulting in 100 trees within a plot of 400 m². The total initial stand density was therefore 2500 trees per hectare in each plot. Each plot was planted with one to five species. Only maritime pine (Pinus pinaster/Ppin) and silver birch (Betula pendula/Bpen) were considered in this data set.
For this study, we have selected 14 plots per blocks. The present data set is composed by data collected in 2014 (7 years-old) on the target trees at the center of the plots in order to avoid edge effects (measured planting locations = 36).
The total height was measured on living trees using a graduate pole. We also measured circumferences at 1.30m height on 7 randomly chosen pines and 7 randomly chosen birches per plot. We estimated missing tree heights and circumferences and tree volumes by:
- Using height-circumference relationships to estimate the circumferences of trees that have not been measured in 2014 by mean of separate generalized additive models for each stand composition and tree density.
- Using the generic model developed by Deleuze et al. (2014) to aboveground tree volumes. We assigned a minimum volume of 0.01m3/ha to the few trees below 1.30m in height (corresponding to the minimum volume found in the data set).
- Eventually we estimated dimensions of dead trees by averaging diameter, height and volume of living trees in the plot
Descriptive variables of 11,004 roots from 69 Pinus pinaster root systems excavated and digitized in 3D
No full textThis data set include 11004 roots from 69 coarse root systems of Pinus pinaster trees. These trees belong from the same local provenance of P. pinaster trees germinated in the field and grown in the same area (forest range of the “Landes de Gascogne” in Southwest France).These trees were aged 3, 4, 6, 13 and 50 years.
The description of excavation procedure of coarse root system can be found in Danjon et al. 2005 and the measurement procedure is described in Danjon and Reubens (2008) and Saint Cast et al. (2019).
The four root traits selected as classifiers, and computed for each root axis (Id Axis), included three geometrics and one vigour traits, as follows:
- CSAco : Basal cross-sectional area (CSA) measured 2 cm from the base of the axis, divided by the tree cross-sectional area at the collar (co) to consider the axis size.
- Tropism intensity is computed as the ratio of the depth difference between the two ends of each excavated root over the length of the root axis. Roots with tropism close to 0 show a high plagiotropism (trend to bend horizontally), those with tropism close to 1 have a positive gravitropism (trend to bend downwards), and those with tropism close to -1 have a negative gravitropism (trend to bend upwards).
- Parent root tropism intensity is the tropism intensity of the parent root of the axis.
- Branching angle is estimated using a vector method. It was defined for all roots from two 10-cm long vectors to describe both the parent root direction before the branching point and the daughter root direction after the branching point (see Fig. 1 in Saint Cast et al. 2019).
The branching order is also given by root axis.
Two calculated attributes can be found in this data set: the root type classification obtained by clustering and the final root type classification (Saint Cast et al., submitted) as:
Order1: taproot
OverSize: Oversize roots were mainly horizontal roots branching from the stump or secondary sinkers in the oldest root systems.
Hh: Horizontal roots branching from horizontal roots
Hv: Horizontal roots branching from vertical roots
Vh: Vertical roots branching from horizontal roots
Vv: Vertical roots branching from vertical roots
Danjon F, Fourcaud T, Bert D (2005) Root architecture and wind-firmness of mature Pinus pinaster. New Phytologist 168:387–400. https://doi.org/10.1111/j.1469-8137.2005.01497.x
Danjon F, Reubens B (2008) Assessing and analyzing 3D architecture of woody root systems, a review of methods and applications in tree and soil stability, resource acquisition and allocation. Plant and Soil 303:1–34. https://doi.org/10.1007/s11104-007-9470-7
Saint Cast C, Meredieu C, Défossez P, et al (2019) Modelling root system development for anchorage of forest trees up to the mature stage, including acclimation to soil constraints: the case of Pinus pinaster. Plant Soil 439:405–430. https://doi.org/10.1007/s11104-019-04039-4
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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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