1,720,976 research outputs found
Modulation of lipid metabolism in Nannochloropsis spp.: understanding metabolic pathways towards the production of oils
No full textAnthropogenic greenhouse gas emissions drive climate change, with agriculture contributing nearly to one-third of global emissions. Significant impacts arise from land use changes like deforestation for livestock and crops, leading to CO2 release, soil degradation and ecosystems loss. Fertilizer and water overuse exacerbate environmental issues. The growth of the global population (projected to exceed 9.5 billion by 2050) will demand increased food production, particularly in oil crops, which occupy 20% of cultivated areas and contribute to land use challenges, especially with palm oil.
Microalgae, such as Nannochloropsis spp., offer a sustainable alternative for lipid production. Known for high photosynthetic rates and valuable biomass, these organisms can grow on non-arable land, using seawater and waste CO2. Nannochloropsis spp. is notable for accumulating lipids and eicosapentaenoic acid (EPA). In the last decades, genetic engineering has been focusing on enhancing lipid yield and understanding fatty acid biosynthesis.
This thesis explores genetic modifications in Nannochloropsis spp. to optimize lipid production. In Chapter 2, a N. gaditana strain with a knockout for plastid desaturase SAD showed a decrease in palmitoleic acid and increased unsaturated fatty acids content, a fatty acid profile more similar to that of palm oil. Chapter 3 examines overexpression of β-ketoacyl-ACP-synthase (KAS), revealing changes in fatty acid profiles without compromising growth or lipid yield yet affecting photosynthesis under nitrogen limitation.
Chapter 4 investigates the role of a unique Apicomplexa-like TPT transporter in carbon flux regulation, finding that its inactivation boosts neutral lipid accumulation under low light. Chapter 5 focuses on ammonium transporters (NgAMT1 and NgAMT2) in nitrogen metabolism, highlighting their roles in ammonium uptake and intracellular trafficking, essential for linking nitrogen availability to lipid metabolism.
These findings offer insights into improving Nannochloropsis-based lipid production, to address both environmental and food system sustainability challenges
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
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
Assisted reproductive technique in women of advanced fertility age
No full textOver the past four decades, the postponement of childbearing has continued to increase, significantly impacting the age of first-time mothers. Female age is the most significant factor influencing clinical outcome in in-vitro fertilization. To overcome the limits of the age-related decline of fertility is a challenge for fertility experts. In the decrease of fertility in late reproductive age, a lot of factors related with advancing women's age and general health can be considered, however the dominant regulator of this age-dependent loss of fertility is the ovary. The key factors in the ovarian aging are oxidative stress, abnormalities of the meiotic spindle, decrease of function and number of oocyte mitochondria, alteration of sirtuins and androgen deficiency. The aim of this review was to assess the main biological factors involved in the female reproductive ageing according to the recent literature, focusing on oocyte-dependent ones, as well as the possible therapeutic strategies in assisted reproductive technique
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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