1,721,015 research outputs found
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
Method for biosynthesis of specific isotope-marked secondary metabolites
No full textDie Erfindung betrifft ein Verfahren zur Biosynthese von spezifisch isotopenmarkierten Sekundärmetaboliten. Zielsetzung der vorliegenden Erfindung war die Entwicklung eines Verfahrens zur spezifischen Markierung von mikrobiellen Sekundärmetaboliten mit stabilen oder radioaktiven Isotopen, mit dem unter stark reduziertem Einsatz markierter Vorstufen höchste Einbau- und Markierungsraten erzielt werden können. Erfindungsgemäß werden mittels gentechnischer Methoden im Genom von bakteriellen bzw. pilzlichen Sekundärmetabolitproduzenten Gene der Aminosäurebiosynthese ausgeschaltet, deren Endprodukte (Aminosäuren) als Donoren funktioneller Gruppen von Sekundärmetaboliten dienen bzw. teilweise oder vollständig in die Molekülstruktur von Sekundärmetaboliten integriert werden. Der Einsatz isotopenmarkierter Substanzen erfolgt dabei wesentlich gezielter als bei dem gegenwärtig eingesetzten Verfahren zur Totalmarkierung, welches auf einer Zugabe von markierten Aminosäuren in ein Kulturmedium beruht. Das erfindungsgemäße Verfahren kann zur gezielten Markierung einer Vielzahl von Naturstoffen, eingesetzt werden. Die besondere Bedeutung des Verfahrens liegt dabei in der Herstellung preiswerter, verlässlicher Referenzsubstanzen/Standards für die moderne, hochsensitive Analytik-Verfahren wie SIDA-MS/MS.The invention relates to a method for biosynthesis of specific isotope-marked secondary metabolites. The invention addresses the problem of developing a method for specific marking of microbial secondary metabolites having stable or radioactive isotopes, by means of which maximum installation and marking rates can be achieved via strongly reduced use of marked precursors. According to the invention, genes of amino acid biosynthesis in the genome of bacterial or fungal secondary metabolite producers are deactivated by means of genetic engineering methods, the final products (amino acids) of which serve as donors of functional groups of secondary metabolites and are partially or completely integrated in the molecular structure of secondary metabolites. The use of isotope-marked substances occurs substantially more specifically according to the invention than in the currently used method of total marking, which is based on an addition of marked amino acids to a culture medium. The method according to the invention can be used for specific marking of a plurality of natural substances. The particular significance of the method lies in the production of inexpensive, reliable reference substances/standards for modern, highly sensitive analytics methods such as SIDA-MS/MS.L'invention concerne un procédé de biosynthèse de métabolites secondaires marqués spécifiquement par des isotopes. L'invention vise à développer un procédé de marquage spécifique des métabolites secondaires microbiens par des isotopes stables ou radioactifs, qui permette d'atteindre des taux d'incorporation et de marquage les plus élevés possible tout en réduisant fortement le recours à des étapes de pré-marquage. Le procédé selon l'invention consiste à neutraliser au moyen de méthodes génétiques dans le génome de producteurs de métabolites secondaires bactériens ou fongiques les gènes de la biosynthèse des acides aminés, dont les produits finaux (acides aminés) servent de donneurs de groupes fonctionnels de métabolites secondaires ou sont en partie ou en totalité intégrés dans la structure moléculaire de métabolites secondaires. L'utilisation de substances marquées par des isotopes se fait alors sensiblement de manière plus ciblée que dans le cas du procédé de marquage total utilisé actuellement, qui repose sur l'addition d'acides aminés marqués dans un milieu de culture. Le procédé selon l'invention peut être utilisé pour le marquage ciblé d'une pluralité de substances naturelles. L'importance particulière du procédé réside dans la production de substances de référence/de normes économiques et fiables pour des procédés d'analyse modernes hautement sensibles, par exemple les procédés d'analyse SIDA-MS/MS
Method for biosynthesis of specific isotope-marked secondary metabolites
No full textDie Erfindung betrifft ein Verfahren zur Biosynthese von spezifisch isotopenmarkierten Sekundärmetaboliten. Zielsetzung der vorliegenden Erfindung war die Entwicklung eines Verfahrens zur spezifischen Markierung von mikrobiellen Sekundärmetaboliten mit stabilen oder radioaktiven Isotopen, mit dem unter stark reduziertem Einsatz markierter Vorstufen höchste Einbau- und Markierungsraten erzielt werden können. Erfindungsgemäß werden mittels gentechnischer Methoden im Genom von bakteriellen bzw. pilzlichen Sekundärmetabolitproduzenten Gene der Aminosäurebiosynthese ausgeschaltet, deren Endprodukte (Aminosäuren) als Donoren funktioneller Gruppen von Sekundärmetaboliten dienen bzw. teilweise oder vollständig in die Molekülstruktur von Sekundärmetaboliten integriert werden. Der Einsatz isotopenmarkierter Substanzen erfolgt dabei wesentlich gezielter als bei dem gegenwärtig eingesetzten Verfahren zur Totalmarkierung, welches auf einer Zugabe von markierten Aminosäuren in ein Kulturmedium beruht. Das erfindungsgemäße Verfahren kann zur gezielten Markierung einer Vielzahl von Naturstoffen, eingesetzt werden. Die besondere Bedeutung des Verfahrens liegt dabei in der Herstellung preiswerter, verlässlicher Referenzsubstanzen/Standards für die moderne, hochsensitive Analytik-Verfahren wie SIDA-MS/MS.The invention relates to a method for biosynthesis of specific isotope-marked secondary metabolites. The invention addresses the problem of developing a method for specific marking of microbial secondary metabolites having stable or radioactive isotopes, by means of which maximum installation and marking rates can be achieved via strongly reduced use of marked precursors. According to the invention, genes of amino acid biosynthesis in the genome of bacterial or fungal secondary metabolite producers are deactivated by means of genetic engineering methods, the final products (amino acids) of which serve as donors of functional groups of secondary metabolites and are partially or completely integrated in the molecular structure of secondary metabolites. The use of isotope-marked substances occurs substantially more specifically according to the invention than in the currently used method of total marking, which is based on an addition of marked amino acids to a culture medium. The method according to the invention can be used for specific marking of a plurality of natural substances. The particular significance of the method lies in the production of inexpensive, reliable reference substances/standards for modern, highly sensitive analytics methods such as SIDA-MS/MS.L'invention concerne un procédé de biosynthèse de métabolites secondaires marqués spécifiquement par des isotopes. L'invention vise à développer un procédé de marquage spécifique des métabolites secondaires microbiens par des isotopes stables ou radioactifs, qui permette d'atteindre des taux d'incorporation et de marquage les plus élevés possible tout en réduisant fortement le recours à des étapes de pré-marquage. Le procédé selon l'invention consiste à neutraliser au moyen de méthodes génétiques dans le génome de producteurs de métabolites secondaires bactériens ou fongiques les gènes de la biosynthèse des acides aminés, dont les produits finaux (acides aminés) servent de donneurs de groupes fonctionnels de métabolites secondaires ou sont en partie ou en totalité intégrés dans la structure moléculaire de métabolites secondaires. L'utilisation de substances marquées par des isotopes se fait alors sensiblement de manière plus ciblée que dans le cas du procédé de marquage total utilisé actuellement, qui repose sur l'addition d'acides aminés marqués dans un milieu de culture. Le procédé selon l'invention peut être utilisé pour le marquage ciblé d'une pluralité de substances naturelles. L'importance particulière du procédé réside dans la production de substances de référence/de normes économiques et fiables pour des procédés d'analyse modernes hautement sensibles, par exemple les procédés d'analyse SIDA-MS/MS
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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