1,720,974 research outputs found
Space flight effects on antioxidant molecules in dry tardigrades : the TARDIKISS experiment
Full text linkThe TARDIKISS (Tardigrades in Space) experiment was part of the Biokon in Space (BIOKIS) payload, a set of multidisciplinary experiments performed during the DAMA (Dark Matter) mission organized by Italian Space Agency and Italian Air Force in 2011. This mission supported the execution of experiments in short duration (16 days) taking the advantage of the microgravity environment on board of the Space Shuttle Endeavour (its last mission STS-134) docked to the International Space Station. TARDIKISS was composed of three sample sets: one flight sample and two ground control samples. These samples provided the biological material used to test as space stressors, including microgravity, affected animal survivability, life cycle, DNA integrity, and pathways of molecules working as antioxidants. In this paper we compared the molecular pathways of some antioxidant molecules, thiobarbituric acid reactive substances, and fatty acid composition between flight and control samples in two tardigrade species, namely, Paramacrobiotus richtersi and Ramazzottius oberhaeuseri. In both species, the activities of ROS scavenging enzymes, the total content of glutathione, and the fatty acids composition between flight and control samples showed few significant differences. TARDIKISS experiment, together with a previous space experiment (TARSE), further confirms that both desiccated and hydrated tardigrades represent useful animal tool for space research
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
TARDIGRADES: MULTICELLULAR ORGANISMS ON BOARD OF THE INTERNATIONAL SPACE STATION
No full textThe experiment “Tardigrades in Space – TARDIKISS” investigated the effects of the permanence in space of small animals (tardigrades), as representatives of multicellular organisms (1,2). TARDIKISS was part of a set of multidisciplinary experiments on board of STS-134 space flight, the last of the shuttle Endeavour (3). The responses to flight conditions of two anhydrobiotic species (Paramacrobiotus richtersi and Ramazzottius oberhaeuseri) were compared. The experiment units were hosted into the Biokon (by Kayser Italia), integrated on Middeck Locker of ISS and flown for 16 days at LEA. Other than the Flight samples (F), two sample sets were used as controls: Laboratory Control (LC) maintained in Modena lab, and Temperature Control (TC) a post-Flight control using the flight temperature profile. For both species, the flight animals did not show differences in survival with regard to LT and TC animals, with the exception between F and TC samples of R. oberhaeuseri (3). In lab, females of P. richtersi from F, LC and TC samples laid eggs which were able to hatch and newborns, when adult, exhibit the capability to reproduce. A comparative analysis of the antioxidant defence between F and TC samples showed no differences between the two groups, with the exception of the peroxidase activity for which a significant increase were evidenced in P. richtersi flight sample. Instead, significant differences were recorded in the activities of antioxidant molecules between the two flight species. In conclusion, microgravity did not significantly affect tardigrade survival and oxidative stress, confirming that tardigrades represent a useful animal tool for space research
Antioxidant metabolism of the tardigrade Macrobiotus richtersi desiccated, active and under space flight
No full textVariations 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
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