1,720,960 research outputs found
Monitoring grapevine water status by unmanned aerial vehicles (UAVs) and plant based sensors
No full textGrowth and Accumulation of Caffeic Acid Derivatives in Echinacea angustifolia DC. var. angustifolia grown in Hydroponic Culture
No full textIn separate experiments conducted in 2007 and 2008, growth and accumulation of selected caffeic acid
derivatives (CADs; i.e., caftaric acid, chlorogenic acid, echinacoside, caffeic acid, cynarin, p-coumaric acid,
ferulic acid and cichoric acid) were determined in Echinacea angustifolia DC. var. angustifolia seedlings
grown in hydroponic culture (floating raft system) at a density of 122 plant m−2 (at planting). Plants
were harvested 11 (2007) or 16 (2008) weeks after transplanting (i.e., 15 or 20 weeks after sowing). In
both years, plants grew vigorously and at harvest approximately half of the plants under observation had
developed one to three inflorescences. In 2008, the root yield (2940 kg ha−1) harvested in nearly eight
months from two consecutive hydroponic cultures was within the yield reported in the literature for
field cultivations lasting two to four years. None of the selected CADs was found in the leaves, while
the inflorescences (stem and capitulum) contained only caftaric acid and echinacoside at concentrations
higher than the detection limits (0.05 mg g−1 dry weight). Echinacoside, cynarin and chlorogenic acid were
found in root tissues at concentrations ranging from 0.36 to 5.25 mg g−1 dry weight. In all plant samples,
echinacoside, which is the marker compound for E. angustifolia material, did not reach the minimum
quality standard (10 mg g−1 dry weight) for the production of standardized extract. We concluded that
short-cycle, high-density greenhouse hydroponic culture stimulates plant growth and root production
in E. angustifolia, but it does not ensure sufficient CADs accumulation in dried roots
The role of LAI and leaf chlorophyll on NDVI estimated by UAV in grapevine canopies
Full text linkDespite the wide use of the Normalized Difference Vegetation Index (NDVI) in precision viticulture, there are no studies aimed at discriminating the contribution of plant biomass from that of leaf chlorophyll on canopy NDVI. Leaf area index (LAI) and leaf chlorophyll (Chl) were concomitantly monitored by ground measurements and projected canopy area (PCA), canopy volume (CV) and NDVI by high resolution UAV multispectral images in fully productive "Sangiovese" grapevines either grown in containers or in the field and subjected to different irrigation regimes over two consecutive years. NDVI values calculated from only vine canopy pixels (NDVIUAV) and NDVI obtained from mixed ground-canopy pixels (simulated Satellite NDVI, NDVISAT) were both evaluated as potential predictor of LAI and leaf Chl concentration.The seasonal patterns of LAI and leaf Chl concentration were affected by irrigation, showing differences depending on field vs container-grown conditions. In situations where a decoupling between LAI and leaf Chl occurred, NDVIUAV and NDVISAT showed different responses: NDVIUAV patterns strictly followed the leaf Chl ones, whereas NDVISAT was more affected by LAI. The coefficient of determination between NDVIUAV and leaf Chl ranged between 0.51 and 0.78, that between NDVIUAV and leaf Chl from 0.01 to 0.76, depending on the irrigation-growing conditions combination. NDVISAT was a better predictor of LAI (R-2=0.69) than NDVIUAV (R-2=0.42). In field-grown vines the relationships between NDVI (both UAV and SAT) and LAI was stronger than in potted ones. The relationships between LAI and PCA (R-2=0.44) or LAI and canopy volume (R-2=0.77) were both significant. The results allowed to confirm the two main hypotheses behind this experiment: i) leaf Chl concentration had a greater impact than LAI on NDVI values obtained from vine canopy pixels (NDVIUAV), whereas NDVISAT was more affected by LAI; ii) The canopy volume from UAV images was a better predictor of LAI than NDVI and the resulting relationship showed a better temporal stability
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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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