1,720,963 research outputs found
Analysis of the role of the pyruvate decarboxylase gene family in Arabidopsis thaliana under low-oxygen conditions
No full text,Proteomic identification of differentially expressed proteins in the anoxic rice coleoptile
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Physiological responses to Megafol® treatments in tomato plants under drought stress: A phenomic and molecular approach
No full textDrought is one of the most significant abiotic stresses that limits the growth and productivity of crop plants. We investigated the physiological and molecular responses of tomato plants treated with Megafol® (Valagro S.p.A), under specific drought conditions. The goal was to evaluate the impact of Megafol®, a biostimulant composed of a complex of vitamins, aminoacids, proteins and betaines, in attenuating the negative physiological responses of drought. Tomato plants were grown in a greenhouse, and physiological parameters were collected using Scanalyzer 3D (LemnaTec, GmbH), a plant phenomics platform. Using this technology it is possible to dynamically study the effects of biostimulants, such as Megafol®, on plant development in terms of early detection of physiological plant stress responses. The results showed that drought-stressed plants treated with Megafol® were healthier in terms of the biomass produced and chlorophyll fluorescence, thus highlighting the higher tolerance to stress of the treated plants. The effects of Megafol® were also studied at a molecular level by analysing the induction of genes typically involved in drought stress responses. Our results demonstrate the efficacy of Megafol® to reduce drought-stress related damage in tomato plants
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
Caratterizzazione fisiologica e molecolare di un mutante nano di Arabidopsis thaliana
No full textUn mutante nano di A. thaliana (L.) Heynh è stato isolato, nel corso di uno screening su turanosio tra linee mutate T-DNA tagged, in quanto ipersensibile a questo analogo non metabolizzabile del saccarosio.
Le principali caratteristiche fenotipiche del mutante nana sono le ridotte dimensioni, un marcato ritardo nella fioritura e le foglie di color verde scuro. Osservazioni al CRIO-SEM hanno indicato come le cellule della lamina fogliare di nana siano più piccole di quelle del wild-type Columbia gl1.
Sono stati identificati due siti di inserzione del T-DNA, mediante la tecnica della TAIL-PCR: (1) sul promotore del gene At3g12700, che codifica per una aspartyl proteasi, ed è simile a una CND41, DNA binding protein chloroplast nucleoids in T. nicotiana; (2) sull’ultimo introne del gene At1g73720, fattore trascrizionale in D. melanogaster, denominato Will Die Slowly.
L’attenzione è stata concentrata su At3g12700, poiché in tabacco è stato identificato un mutante knock-out per un gene simile al CND41, con le stesse caratteristiche fenotipiche; il relativo sito di inserzione è stato completamente sequenziato e la sua espressione analizzata mediante Real-Time PCR. In un primo momento sembrava che nana over-esprimesse At3g12700, ma un’analisi più accurata ha rilevato una possibile modulazione del gene da parte dell’intensità luminosa e una variazione nel livello di espressione, in funzione del ciclo circadiano.
È risultato interessante come l’espressione di At3g12700 sia indotto dalla presenza nel mezzo agarizzato di saccarosio 90mM, suggerendo una possibile interazione tra lo sugar sensing e la biosintesi delle gibberelline.
Inoltre, le dimensioni e la forma delle foglie sono state ristabilite a quelle di gl1 con l’applicazione di gibberelline in una soluzione di metanolo, direttamente sull’apice meristematico, indicando che una riduzione nel contenuto di GAs è la causa principale del fenomeno di nanismo. Per questo motivo, sono state quantificate le GAs endogene del mutante, rispetto a quelle del wild-type, mediante GC-MS. Sono state così individuate delle variazioni nel contenuto delle GAs in nana
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