1,720,967 research outputs found
Is cell composition related to the phylogeny of microalgae? An investigation using Hierarchical Cluster Analysis of Fourier Transform Infrared spectra of whole cells.
No full textFourier Transform Infra-Red (FTIR) spectroscopy was used to investigate whether algae belonging to the
green evolutionary lineage and algae belonging to the red evolutionary lineage consistently differ for
their biomass composition and for the way their composition responds to changes in NO3− availability.
For this purpose, the FTIR spectra of eleven algal species cultured in media containing different amount
of NO3− were subjected to Hierarchical Cluster Analysis (HCA). The same analysis was conducted on the
differential FTIR spectra of cells grown at different NO3− concentrations. Although the organic composition
of cells was affected by the availability of NO3−, the analysis of its change did not elicit a clear
relationship with the phylogenetic position of the species used. However, when the two evolutionary
lineages, and not the individual species, are compared, some differences emerge: the species belonging
to the green lineage reorganize their biomass composition similarly in response to variations in N availability,
whereas the species of the red lineage modulate their allocation patterns more heterogeneously.
This difference may contribute to the ecological fitness of microalgae and may have had an influence on
the evolutionary trajectories of phytoplankton groups
Taxonomy and growth conditions concur to determine the energetic suitability of fatty acid complements in algae
No full textWe hypothesize that, in algae, carbon allocation to lipids depends on the combined effects of the metabolic constraints imposed by the genotype (i.e., species-specific differences in composition) and on the acclimation responses (phenotype) to changes in the stoichiometry of available inorganic carbon (for photosynthesis) and nitrogen (primarily for amino acids, protein, and nucleic acid synthesis). We thus cultured three taxonomically distinct algae, the green alga Dunaliella salina, the diatom Thalassiosira pseudonana, and the dinoflagellate Protoceratium reticulatum, at four nitrate concentrations and constant inorganic carbon. Since energy availability also directly impacts carbon partitioning, we studied the effect of irradiance on the oil quality of P. reticulatum. We used Fourier transform infrared (FTIR) spectroscopy to study carbon allocation and biomass reduction level and gas chromatography for fatty acid analysis. The fatty acid complements of the three species were different; within each species, growth conditions substantially altered oil quality. We ranked the oils in terms of their suitability as biodiesels, using international standards as reference. We believe that this approach may help to identify the appropriate combination of taxa and culture conditions for algal biodiesel production and in general offers insight on carbon allocation to fatty acids
Ecological and evolutionary implications of carbon allocation in marine phytoplankton as a function of nitrogen availability: a FTIR spectroscopy approach
No full textAn imbalance in the cellular C:N ratio may appreciably affect C allocation in algal cells. The consequences of these rearrangements of cellular pools on cell energetics, ecological fitness, and evolutionary trajectories are little known, although they are expected to be substantial. We investigated the fate of C in 11 microalgae cultured semi continuously at three [NO3-] and constant pCO2. We developed a new computational method for the semiquantitative use of Fourier transform infrared (FTIR) spectroscopy data for the determination of macromolecular composition. No obvious relationship was observed between the taxonomy and the allocation strategies adopted by the 11 species considered in this study. Not all species responded to a lower N availability by accumulating lipids or carbohydrates: Dunaliella parva W. Lerche and Thalassiosira pseudonana Hasle et Heimdal were homeostatic with respect to organic cell composition. A hyperbolic dependence of the lipid concentration from cell volume was observed. The level of reduction of organic constituents of green algae was parabolically related to size and was modulated in response to changes in N availability; the same was not true for the species bearing a ‘‘red’’ chloroplast. The above observations are discussed with respect to phytoplankton species composition and palatability for grazers, oleogenesis, and overall cell energetics
A Machine Vision System for Manual Assembly Line Monitoring
No full textCustomers are asking more and more customized products and expect to receive them in really short times. That is only reachable if there is horizontal and vertical integration, together with high information availability and transparency inside a company. When the production is not fully automatized, i.e. in those companies where the assembly or the production still relies on manual work of people, the monitoring of the line production, in terms of number of pieces produced, may be tricky due to the inevitable variability that operators add to the process, thus making essential the creation of smart systems able to deal with such complex environments and autonomously monitor them. Computer vision systems can be customized and very smart in various contexts, if properly modeled. In this paper we are going to describe the developed Machine Vision algorithm that, building upon BLOB (Binary Large Objects) analysis, is able to detect and count objects produced in a complex industrial context of manual assembly. The developed algorithm would then be compared to a more robust one taken as reference point for a comparison. The comparison between our algorithm and the Machine Learning-based Detector aims at showing the comparable Accuracy, Specificity and Sensitivity of our method, together with its higher versatility and processing speed, thus making it applicable in the plant-wide real-time monitoring of the manual assembly lines
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
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