1,720,963 research outputs found
Engels e Hegel: una riconsiderazione critica a muovere dal problema dell’“essenza”
No full textThe article addresses three problems: the relationship between philosophy and science in Engels and Hegel, that between the critique of political economy as interpreted by Engels and the Hegelian doctrine of essence, and that of the nature of the logical-ontological presupposition in Hegel and Engels
Engels duecento anni dopo (1820-2020). Atti del Convegno internazionale di Studi (Catania, 14-15 dicembre 2020)
No full text
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
GAMMA-PGA: Production and characterization of a versatile biopolymer by B. subtilis laboratory strains
No full textIn recent years the interest for potential applications of natural biopolymers has tremendously increased due to the growing demand of industrial processes based on safe raw materials. Poly γ-glutamic acid (γ-PGA) is a versatile unusual, water-soluble, anionic homopolyamide that is raising considerable industrial interests for the multitude of its potential applications. It is efficiently purified by natural bacterial isolates, mainly belonging to the genus Bacillus. Its cost is currently estimated to be much higher than that of conventional materials in current use and, for the moment, it is very difficult to prepare such high-molecular-weight polymer by chemical synthesis. For the industrial application of γ-PGA it is necessary to enhance its productivity and to find optimal fermentation conditions.
Recently, a new Bacillus subtilis producer strain has been derived from the fully genetically characterised laboratory strain 168 (1). The genetic, biochemical and physiological knowledge accumulated in such model organism allowed to devise genetic strategies for strain improvement and setting up of suitable growth conditions, overcoming the heuristic approach thus far applied with wild producers.
We have data showing the success of such strategic genetic engineering approaches: mutant strains with improved and sustained accumulation of the product have been obtained by introducing selected mutations.
The purification procedure has been carefully analysed and purity and size of the polymer have been checked by NMR and GPC. Copurification of enzymes and other by-products will be shown and discussed. The result is a competitive γ-PGA producer strain.
1) Osera, Amati, Calvio, Galizzi (2009). Microbiology, 155:2282-228
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
Knockout of pgdS and ggt genes improves γ-PGA yield in B. subtilis.
No full textOne of the emerging biopolymers that are currently under active investigation is bacterial poly (γ-glutamic acid) (γ-PGA). However, before its full industrial exploitation, a substantial increase in microbial productivity is required. γ-PGA obtained from the Bacillus subtilis laboratory strain 168 offers the advantage of a producer characterized by a well defined genetic framework and simple manipulation techniques. In this strain, the knockout of genes for the major γ-PGA degrading enzymes, pgdS and ggt, leads to a considerable improvement in polymer yield, which attains levels analogous to the top wild γ-PGA producer strains. This study highlights the convenience of using the laboratory strain of B. subtilis over wild isolates in designing strain improvement strategies aimed at increasing γ-PGA productivity
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