1,721,066 research outputs found
The Application of Micro- and Nano-Sized Zinc Oxide Particles Differently Triggers Seed Germination in <i>Ocimum basilicum</i> L., <i>Lactuca sativa</i> L., and <i>Lepidium sativum</i> L. under Controlled Conditions
Full text linkZinc oxide (ZnO) particles have recently received attention in different agriculture sectors as new technologies and practices are entering into force with limited adverse effects on the environment. However, various works have reported both positive or negative effects on plants. The present study focused on an evaluation of the effects of four different new micro- and nano-sized ZnO particles (namely, Desert Roses (DRs), MultiPods (MPs), NanoFlakes (NFs), and NanoParticles (NPs)) on the seed germination traits of Ocimum basilicum L., Lactuca sativa L., and Lepidium sativum L. ZnO particles were applied at concentrations of 12.5 ppm, 25 ppm, and 50 ppm. Seeds moistened with deionized water were used as a control. All the particles were characterized by field emission scanning electron microscopy, and their production of Reactive Oxygen Species (ROS) under seed germination conditions was evaluated through electron paramagnetic resonance spectroscopy. Seeds of each species were put on filter paper under controlled conditions in both dark and light photoperiods. In this bioassay, the final germination percentage (FGP), early root length, and index of germination were evaluated. The results showed a wide variability of response to the type and concentration of ZnO particles and to the applied photoperiod of the three studied species. O. basilicum FGP increased when treated with NPs and DRs already at the lowest concentration and especially in light conditions with values significantly superior to those of the control (71.1%, 69.4%, and 52.2%, respectively). At higher concentrations, phytotoxicity on root length was observed, with a reduction of circa 30% in comparison to untreated seeds. On the contrary, in L. sativum, a phytotoxic effect was seen in radicle length with all the used ZnO particles and concentrations. L. sativa seeds did not show significant effects due to the type of particles, with a reduction in FGP only at higher concentrations and particularly in light conditions. Upon light irradiation, different levels of ROS were counted by the application of ZnO particles. DRs produced the highest amount of DMPO-OH adduct (up to 2.7 × 10−5 M) followed by the NP type (2.0 × 10−5 M). Taking together all these findings, the seeds’ coat morphology, their ability to absorb ZnO particles, and the ROS production in light conditions are indeed crucial players in the application of these formulations in seed germination
Drought stress adaptation modulates plant secondary metabolite production in Salvia dolomitica Codd
Full text linkSage is an important medicinal and aromatic plant. While Salvia officinalis and S. miltiorrhiza have been widely studied, little information regarding S. dolomitica exists, although it has recently attracted attention due to its anti-plasmodial and anti-inflammatory properties. This study investigated the performance and metabolic profile of this species in response to two drought treatments (moderate or severe) relative to well-watered control plants. Changes in growth and ecophysiological traits, as well as in bioactive and volatile compounds and essential oil production were determined. Given that terpenoids are the most representative class of secondary metabolites, the gene expression of key enzymes of terpenoid biosynthesis was also investigated. Moderate drought stimulated a decline in leaf water potential, growth and stomatal conductance, as well as an increase in deyhdrin expression. Serious stress symptoms occurred only in severe drought-stressed plants, where a decline in net photosynthesis and transpiration and an increase in endogenous abscisic acid was observed. Both drought stress conditions led to modulate the expression of some genes involved in biogenic volatile organic compound and essential oil biosynthesis and metabolic profile. In particular, drought induced an increase in sesquiterpene production, a class of terpenoids that is important in the food, cosmetics, and pharmaceutical industries. Thus, controlled drought, in addition to water savings during cultivation, can be applied to improve the production of secondary metabolites in S. dolomitica
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
Latitude and altitude influence secondary metabolite production in peripheral alpine populations of the mediterranean species lavandula angustifolia mill
Full text linkLavandula angustifolia Mill. has a great economic importance in perfumery, cosmetics, food manufacturing, aromatherapy, and pharmaceutical industry. This species finds its phytosociological optimum in the sub-Mediterranean region. Latitudinal and altitudinal gradients are expected to affect species diversification in peripheral alpine populations. In this study, phenotypic traits including morphometric parameters, volatile organic compounds (VOCs) and essential oils (EOs) were analyzed in lavender peripheral populations selected in order to explore different ecological conditions. Plants were cultivated under uniform conditions to observe variations due to the genetic adaptation to native environments and to exclude the short-termresponse to environmental factors. Results showed qualitatively and quantitatively intra-specific variations in secondary metabolites, mainly along the latitudinal gradient, while minor effect was attributable to the altitude. This latter affected more the morphometric parameters. As the latitude augmented, VOCs showed lower content of monoterpene hydrocarbon (mh) and higher content of oxygenated monoterpenes (om); whereas EOs showed higher content of mh and non-terpene derivatives (nt) and lower content of sesquiterpene hydrocarbons (sh). Lavender aroma and EO composition varied in every population, for a total of 88 and 104 compounds identified, respectively. Eleven and 13 compounds were responsible for 95%of the dissimilarity, with linalool, linalyl acetate and 1,8-cineole as major contributors. As the latitude augmented, linalool decreased and 1,8-cineole increased while linalyl acetate content was unaffected. These results are discussed with regards to the potential adoption of the lavender peripheral alpine populations for the improvement of quality and productivity of lavender cultivations, especially in mountainous areas
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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