1,721,008 research outputs found
Combining ability estimates of sulfate uptake efficiency in maize
No full textPlant root nutrient uptake efficiency may be expressed by the kinetic parameters, Vmax and Km, as well as by normal enzymatic reactions. These parameters are apparently useful indices of the level of adaptation of genotypes to the nutrient conditions in the soil. Moreover, sulfate uptake capacity has been considered a valuable index for selecting superior hybrid characterized by both high grain yield and efficiency in nutrient uptake. Therefore, the purpose of this research was to determine combining ability for sulfate uptake, in a diallel series of maize hybrids among five inbreds. Wide differences among the 20 single crosses were obtained for Vmax and Km. The general and specific combining ability mean squares were significant and important for each trait, indicating the presence of considerable amount of both additive and nonadditive gene effects in the control of sulfate uptake. In addition, maternal and nonmaternal components of F1 reciprocal variation showed sizeable effects on all the traits considered. A relatively high correlation was also detected between Vmax and Km. However, both traits displayed enough variation to suggest that simultaneous improvement of both Vmax and Km should be feasible. A further noteworthy finding in this study was the identification of one inbred line, which was the best overall parent for improving both affinity and velocity strategies of sulfate uptak
Genetic variation of sulfate translocation in maize
No full textThe ability of a crop species to absorb and translocate a large amount of nutrients is a primary plant property which affects the efficiency of utilization of available inorganic resources. The objective of this investigation was to examine genotypic differences for the kinetic parameters, Vmax and Km, of sulfate translocation from roots to leaves, in a diallel series of maize single crosses, involving five inbred lines. The results showed that large differences exist among the 20 F1 hybrids tested for both kinetic parameters of sulfate translocation. Moreover, it was revealed that both additive and non-additive genetic effects control the expression of the various characters examined. However, only non-additive genetic effects were found to be of importance for the Km parameters. In addition, significant variations due to reciprocal effects were found for both Vmax and Km parameters. A reasonably unfavourable correlation was also detected between Vmax and Km. However, it appears that maize genotypes could be developed that would be more efficient in utilizing the available inorganic resources from soil solution.
Abstract (Italian) La capacita di una pianta di assorbire e traslocare una rilevante quota di elementi nutritivi influenza l'efficienza di utilizzazione delle risorse inorganiche disponibili nel terreno. Il presente lavoro prevede una analisi delle differenze genotipiche relative all'abilita di traslocazione dei solfati dal sistema radicale all'apparato fogliare, espressa tramite i parametri Km e Vmax, in una serie di ibridi F1 derivata da una rete di incroci diallelici tra 5 linee pure di mais. I risultati ottenuti mostrano sostanziali differenze, tra i 20 ibridi analizzati, per la capacita di traslocazione dei solfati, sia per la Vmax sia per la Km. E' stato, inoltre, osservato che nel controllo genetico della traslocazione dei solfati, espressa dai parametri Km e Vmax intervengono effetti genetici additivi e non additivi. Tuttavia, solo per il parametri Km gli effetti genetici non additivi sono risultati importanti. Per entrambi i parametri Vmax e Km e stata anche accertata la presenza di significativa variabilita ascrivibile ad effetti reciproci. E' stata, infine, osservata la presenza di una sensibile correlazione tra Vmax e Km. Sembra, tuttavia, possibile la sintesi di genotipi di mais piu efficienti nella utilizzazione di sostanze minerali presenti nel terreno
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
Role of the transcriptional regulator opaque2 in carbon partitioning between starch and proteins in the sink
No full textVariations 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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