1,720,970 research outputs found
Estimation of pore-water electrical conductivity in soilless tomatoes cultivation using an interpretable machine learning model
Full text linkSoilless culture is widely adopted for improving produce quality and yield and increasing input efficiency. Most of the benefits potentially achievable in soilless systems are possible through precise and continuous management and adjustment of plant nutrition. Under operational conditions, the electrical conductivity (EC) is the main driving parameter leading fertigation strategies, but its measure in the drainage water can be not completely representative of the root zone in the growing medium. Nowadays low-cost sensors can be adopted to measure bulk EC (ECb) in the substrate. The Hilhorst equation is commonly used to convert the ECb into pore-water EC (ECw). This equation is widely calibrated for soil cultivation, but unable to perform properly for soilless substrate with high moisture content and water permittivity. In this work, two cultivation cycles of cherry tomato, managed in a closed-loop soilless system, were used to calibrate and validate two alternative models to the above equation (i.e., generalized additive model - GAM, and extreme gradient boost model - XGBoost). The models predicted ECw from the ECb recorded by substrate sensors. Plants were grown in rockwool using two different strategies for nutrient solution refill achieving different ECw trends during the cultivation. The Hilhorst equation confirmed its unsuitability for ECw prediction in soilless systems. ECw prediction through GAM was not satisfying at low and high ECw values. XGBoost was the most suitable model for ECw estimation, particularly at extreme EC values
Populus alba tolerates and efficiently removes caffeine and zinc excesses using an organ allocation strategy
No full textMixed inorganic and organic contaminations are one of the main challenges in phytoremediation, due to the higher complexity derived by pollutant interactions and the increase of phytotoxicity. The cultivation of fast-growing poplars for removing contaminants from water could be a low-cost and flexible choice. The main objective of this study was to evaluate the tolerance of a poplar species (Populus alba ‘Villafranca’ clone) to irrigation with water contaminated with zinc (Zn) and caffeine (CFN). Poplars were maintained in hydroponic and exposed to four different treatments (Control, CFN, Zn and Zn + CFN) over 7 days. Poplar showed a good tolerance to Zn and CFN treatments, without any symptom of phytotoxicity. However, the type of treatment affected the contaminant dynamics in the plant-water system and a pollutant partitioning was observed among organs, with a higher accumulation of Zn in root (472 ± 128.7 mg kg− 1 DW) and CFN in shoot (30 ± 4.5 μg g− 1 FW). Under mixed condition, the CFN uptake significantly increased in root (+ 40%) and stem (+ 28%) while the Zn concentration decreased in leaves (-19%). A focus on the potential role of natural resistance-associated macrophage proteins (NRAMPs) in divalent metal transport has been performed. A down-regulation of NRAMP1.3 was detected in roots of plants exposed to CFN treatment in relation to an increase of Mn concentration. Data confirmed the suitability of Populus alba for the remediation of multi contaminated water
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
Daily osmotic adjustments in stem may be good predictors of water stress intensity in poplar
No full textDrought events impair the carbon and water balances in plants. Climate changes highlight the importance to understand the limits of woody species to reallocate carbon in different processes and the mechanisms driving the osmotic adjustments during the day under stress. In this frame, the aim of this work was to investigate the plant capability to shift energy among competing sinks and preserve the osmotic balance during the day under severe short periods of water deficit. The role of carbohydrates as osmolytes as well as energy sources was investigated in poplar plants. Results highlighted that during water deficit soluble sugars, derived both from the new synthetised carbon and starch degradation, were principally convoyed in the bark. This increase in carbohydrates allowed the maintenance of a water reserve used during the day to prevent a water decrease within the xylem. The decrease of xylem sap osmotic potential during the night, driven by an increase of K, Ca, and fructose (+0.46, 0.52, and 0.26 mg ml−1 in water limited plants after 8 days of withholding water, respectively), probably further attracted water into the xylem. This response mechanism increased at higher water deficit intensity. The little variations in carbohydrates and mineral elements within the leaves highlighted the main role of sinks rather than sources in the early response to water deficit
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