1,720,968 research outputs found
The unicellular green microalga Botryosphaerella sudetica links plant‐like light protection with an algal lifestyle
No full textSummary Nonphotochemical quenching (NPQ) mechanisms fine‐tune light utilisation in the photosynthetic antenna, for example, in response to excess light, to prevent photodamage. NPQ comprises distinct mechanisms, all contributing to photoprotection but acting on different time scales. Preferences for individual mechanisms and NPQ composition are proposed to reflect the organism's lifestyle, especially regarding sessile vs motile styles, with the latter enabling photophobic responses. We analysed photoprotection in the nonmotile, unicellular chlorophycean microalga Botryosphaerella sudetica , belonging to a genus known to form high‐light‐exposed floating aquatic biofilms. Growth, Chl fluorescence, its nuclear genome, and the expression of photoprotective genes were analysed in comparison with the motile chlorophycean microalga Chlamydomonas reinhardtii . These analyses revealed that B. sudetica is, in contrast to C. reinhardtii , equipped with a constitutive energy‐dependent quenching (qE) mechanism based on the constitutive accumulation of protein PSBS, the thylakoid lumen pH‐sensor, found throughout the green plant lineage. While qE was the predominant NPQ mechanism in B. sudetica and required zeaxanthin formation, state transitions (qT), which largely contributed to NPQ in C. reinhardtii , played a minor role. These data demonstrate that a core set of NPQ mechanisms conserved in the Viridiplantae is shuffled to meet better the adaptive requirements imposed by the habitat
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
Systematic metabolic characterization of hydrocarbon and exo-polysaccharide producing microalga Botryococcus braunii
Full text linkChaudhari S. Systematic metabolic characterization of hydrocarbon and exo-polysaccharide producing microalga Botryococcus braunii. Bielefeld: Universität Bielefeld; 2018.Renewable energy in the form of bio-diesel, bio-methane, bio-hydrogen, and hydrocarbons from microalgal biomass is gaining attention for research in recent years. The use of microalgal biomass as a source of proteins, photosynthetic pigments, antioxidants, peptides, fatty acids and polysaccharides have led to many applications in biofuels, food and feed industry and for its use in the pharmaceutical and cosmetic industries.
The green colony forming microalga Botryococcus braunii is well known for its ability to produce large amount of hydrocarbons (~75% of dry biomass) and exo-polysaccharides and is divided into three different races (A, B and L), based on the types of hydrocarbon they produce. The production of metabolically expensive compounds such as hydrocarbons and polysaccharides is one of the main reasons for its slow growth rate and is largely depend on the physiological state of the cells. Apart from slow growth rate, variations across different races and strains in terms of growth behavior, formation of product and biomass yield are some of the main challenges for the commercial applications of this microalga. This leads to the identification and characterization of novel strains of B. braunii which can perform better despite of challenges associated with it.
Therefore, the current study focuses on the systematic metabolic characterization and comparison of B.braunii race A and race B strains in order to address some of the challenges associated with its slow growth rate and product formation. Furthermore, the result obtained in the current work shows the impact of different physiological state of the cell on product formation and on overall metabolome profile. Additionally, the strains of race A and race B were compared with respect to their growth behavior, metabolome profile and product formation abilities.
The study revealed that the investigated B. braunii strains differed greatly in terms of biomass accumulation and hydrocarbon/EPS formation. Race A and race B strains have distinct growth and hydrocarbon/EPS formation phases depending on their physiological state, based on the total chlorophyll content. Comparison between race A and B strains revealed extended linear growth phase for race B strain AC 761. Moreover, the hydrocarbon production in race A strain CCAP 807/2 and race B strain AC 761 differed during the duration of cultivation. For race A strain (CCAP 807/2) the hydrocarbon biosynthesis was promoted during late linear and early stationary phase, whereas race B produces hydrocarbons continuously from the beginning of the cultivation and the hydrocarbon productivity is maximum during the linear phase.
Besides, the primary metabolome analysis of race A and B strains also showed significant differences in the abundance of metabolites related to carbohydrate metabolism especially sucrose. Moreover, race B showed higher intracellular lipid content than race A strains.
Strikingly, even though the race A strains CCALA 778 and CCAP 807/2 showed similar growth behavior, they significantly differed in their ability to produce hydrocarbons. CCALA 778 was majorly carbohydrate producer with presence of only detectable amount of hydrocarbons whereas CCAP 807/2 was able to produce both hydrocarbons and carbohydrates. Furthermore, the gradual increase in the hydrocarbon formation was proportional to the decrease in oleic acid. Notably, intracellular lipid content in CCAP 807/2 was two-fold more than CCALA 778. The very long chain fatty acid (VLCFAs) which are intermediates for the hydrocarbon biosynthesis in race A were detected in both race A and race B strains. In addition, the primary metabolome analysis showed sucrose as the most abundant metabolite in both the strains of race A.
Altogether, this work presents for the first time the distinct and shared characteristics of growth behavior, metabolome and product formation for the B. braunii race A strains CCLA778 and CCAP 807/2 with race B strain AC761. In addition, the results in this study also show the potential link and impact of different physiological state of the cell on product formation and on the overall metabolome profile
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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