1,720,957 research outputs found
The effect of seed priming with melatonin on improving the tolerance of Zea mays L. var saccharata to paraquat-induced oxidative stress through photosynthetic systems and enzymatic antioxidant activities
Full text linkMelatonin is essential in improving plant's biotic as well as abiotic stress tolerance, especially detoxification of herbicides. The purpose of the present research study was studying the probable positive impacts of melatonin on the enhancement of the growth as well as oxidative stress tolerance in sweet corn (Zea mays L. var saccharata). For this purpose, the effects of seven treatments of priming (hydro priming with water (H), melatonin (M) priming with 25, 50, 100, 150 and 200 mu M and non-priming (D)) and three doses of paraquat (PQ: 0, 5 and 7.5 L per hectare of recommended dose (5 L per hectare)) on physiological as well as biochemical responses belong to sweet corn were probed according to a completely randomized factorial design involving three replicates. The obtained results provided the indication that applying PQ, particularly at high levels (7.5 L ha -1), in the absence of priming, enhanced the rate of herbicide injury by 49.2%, as compared with 5 L ha -1, by increasing free radical production rate and membrane lipids' peroxidation, in addition to inhibiting the process of photosynthesis. Seed priming with melatonin positively impacted PQ exposed plants, even under the enhanced concentration of PQ (7.5 L ha -1). The maximum protection for the sweet corn plants could be observed at M150. Co-application of melatonin (M150) and PQ herbicide (7.5 L ha -1) reduced H2O2, MDA and herbicide injury by 3.0, 2.1 and 4.6 times, respectively, while it increased SOD, CAT, APX and POD by 2.9, 4.6, 2.4 and 2.0 times, respectively, as compared with D treatments. The obtained results provided the indication that melatonin priming could raise tolerance to oxidative stress which is triggered by PQ in sweet corn with the enhancement of antioxidant en-zymes' activity and reduction of herbicide injury
Glomus versiforme and Micrococcus yunnanensis reduce the negative effects of salinity stress by regulating the redox state and ion homeostasis in Brassica napus L. crops
No full textSalinity stress is a major threat that negatively affects plant growth and production in arid and semi- arid regions. Application of biofertilizers could mitigate this stress. Accordingly, a pot experiment was conducted on rapeseed grown under salinity stress (0, 5, 10, and 15 dS m−1) while considering the following additives: (1) AMF (non-inoculated and inoculated with Glomus versiforme) and (2) PGPR (non-inoculated and inoculated with Micrococcus yunnanensis). The present results showed that salinity stress led to significant reductions in growth, yield, yield components, and physiological attributes, while raising the Na+/K+ ratio. However, with the application of PGPR and AMF, the increased salinity tolerance of rapeseed resulted in a significant improvement in redox status and ion homeostasis. They considerably improved antioxidant enzymatic activity and plant nutrition status. Furthermore, the co-inoculation of PGPR and AMF increased chlorophyll a, chlorophyll b, carotenoids, photosynthesis rate, and percentage of rapeseed oil under 15 dS m−1 1.7-, 1.8-, 2.3-, 2.0- and 1.3-times, respectively, compared with the non-inoculation treatment. These findings indicate that the integral application of PGPR and AMF is essential for alleviating salinity stress
Alleviating salinity stress in Cyamopsis tetragonoloba L. seedlings through foliar application of silicon or melatonin in arid and semi-desert environments
No full textSalinity stress can be deemed as an important challenge extremely affecting crop growth as well as development. Therefore, it is important to improve its tolerance to salinity stress, in arid as well as semiarid regions. Thus, this experiment explored the influence of foliar usage of plant growth-stimulating substances with different concentrations (C: control, melatonin (M1: 100, M2: 200 and M3:400 μM) and silicon (Si1: 5.4, Si2: 10.8 and Si3: 16.2 mM)) on some physiological as well as biochemical attributes of Cyamopsis tetragonoloba L. (guar) seedlings under five salinity levels (S1: no-salt treatment, S2: 5, S3: 10, S4: 15 and S5: 20 dS m−1). With increasing salinity, shoot dry weight, Fv/Fm, F′v/F′m, ΦPSII, qp, qL, Rfd, ETR, photosynthetic pigments, membrane stability index, as well as relative water content were gradually reduced in salt-stressed guar, as comparison is made to the non-saline conditions. However, foliar usage of plant growth-stimulating substances was effective in improving guar tolerance to salinity by elevating the DPPH radical scavenging capacity and anthocyanin, thus enhancing membrane stability index, improving the electron's transport rate, reducing electrolyte leakage and decreasing the damage affecting the reaction center of PSII, as comparison is made with control. Such positive effects were exhibited in elevating growth under salinity stress. Si3 treatment demonstrated the best response under salinity stress, as compared with the other treatments. Consequently, foliar usage of silicon or melatonin in salt-stressed guar seedlings can serve an efficient method to improve salt tolerance under salinity stress in arid and semiarid regions
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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