1,720,976 research outputs found
Dora on Bobbie, Anzac Day, South Australia, 13 October 1915 /
No full textTitle devised by cataloguer.; Part of the: Jim Davidson Australian postcard collection, 1880-1980.; Condition: Silvering.; Inscription: "Taken Anzac Day, 13 October 1915. Horse Bobby, Owner J? Keast, rider Dora Geeckie"--In ink on image; "Photo by W.S. Smith 293 Pirie St. Adelaide. S. Aust."--Printed on reverse; correspondence on reverse.; Also available online at: http://nla.gov.au/nla.pic-vn6448915
Sarcolipin uncouples hydrolysis of ATP from accumulation of Ca2+ by the Ca2+-ATPase of skeletal-muscle sarcoplasmic reticulum
No full textSarcolipin (SLN) is a small peptide found in the sarcoplasmic reticulum of skeletal muscle. It is predicted to contain a single hydrophobic transmembrane a-helix. Fluorescence emission spectra for the single Trp residue of SLN suggest that SLN incorporates fully into bilayers of dioleoylphosphatidylcholine, but only partially into bilayers of phosphatidylcholines with long (C22 or C24) fatty acyl chains. The fluorescence of SLN is quenched in bilayers of dibromostearoylphosphatidylcholine, also consistent with incorporation into the lipid bilayer. SLN was reconstituted with the Ca2+-ATPase of skeletal-muscle sarcoplasmic reticulum. Even at a 50:1 molar ratio of SLN/ATPase, SLN had no significant effect on the rate of ATP hydrolysis by the ATPase or on the Ca2+-dependence of ATP hydrolysis. However, at a molar ratio of SLN/ATPase of 2:1 or higher the presence of SLN resulted in a marked decrease in the level of accumulation of Ca2+ by reconstituted vesicles. The effect of SLN was structurally specific and did not result from a breakdown in the vesicular structure or from the formation of non-specific ion channels. Vesicles were impermeable to Ca2+ in the absence of ATP in the external medium. The effects of SLN on accumulation of Ca2+ can be simulated assuming that SLN increases the rate of slippage on the ATPase and the rate of passive leak of Ca2+ mediated by the ATPase. It is suggested that the presence of SLN could be important in non-shivering thermogenesis, a process in which heat is generated by hydrolysis of ATP by skeletal-muscle sarcoplasmic reticulum.<br/
The Subject/Object Relationship According to the Phenomenology of Life of Anna-Teresa Tymieniecka: Discovering the Metamorphic Logos of the Ontopoiesis of Life
No full textThe paper will focus on the evolution that the subject/object relationship has had in the transition from classical Phenomenology to the Phenomenology of life. In particular, we will outline the theoretical path that led the reflection of A.-T. Tymieniecka to highlight the fundamentally metamorphic articulation of the logos of life, the only way through which the natural constructivism of life and the creative ontopoiesis of the human condition can be combined. This phenomenological discovery opens up new scenarios of meaning to deal with the recent ecological problems related to the environment and post-humanism
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
Applying neutral drift to the directed molecular evolution of a β-glucuronidase into a β-galactosidase: Two different evolutionary pathways lead to the same variant
Full text linkAbstract Background Directed protein evolution has been used to modify protein activity and research has been carried out to enhance the production of high quality mutant libraries. Many theoretical approaches suggest that allowing a population to undergo neutral selection may be valuable in directed evolution experiments. Findings Here we report on an investigation into the value of neutral selection in a classical model system for directed evolution, the conversion of the E. coli β-glucuronidase to a β-galactosidase activity. We find that neutral selection, i.e. selection for retaining glucuronidase activity, can efficiently identify the majority of sites of mutation that have been identified as beneficial for galactosidase activity in previous experiments. Each variant demonstrating increased galactosidase activity identified by our neutral drift experiments contained a mutation at one of four sites, T509, S557, N566 or W529. All of these sites have previously been identified using direct selection for beta galactosidase activity. Conclusions Our results are consistent with others that show that a neutral selection approach can be effective in selecting improved variants. However, we interpret our results to show that neutral selection is, in this case, not a more efficient approach than conventional directed evolution approaches. However, the neutral approach is likely to be beneficial when the resulting library can be screened for a range of related activities. More detailed statistical studies to resolve the apparent differences between this system and others are likely to be a fruitful avenue for future research.</p
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
The Work of Art as a Living System: A Deweyan Approach
No full textThis paper aims to develop Dewey’s aesthetics in relation to the epistemology of complexity. The focus is particularly on the convergence between a work of art and a living system. Indeed, a work of art, much like a living system, is a unity in variety, being integrated and differentiated. This characteristic is not the result of linear causality, for which each part affects only the contiguous aspects, but the consequence of dynamics of the whole (or, of the field) coordinating the activities of the elements through to their most remote junctions. Every part “feels” the whole, which in turn is realized via articulation in all its parts. Congruently, a work of art contains a perfect integration between “spiritual” and “sensorial” levels, between “bodily” and “ideal.” Thus, it is evident that amongst the various levels comprising a work of art, there is continuity. Ultimately, a work of art is the result of a historical process during which it advances, interacting with the medium, like a living organism that develops, acquiring articulation and volume, learning from experience, embodying and internalizing the learned meanings. In developing this perspective, the concepts of emergence and organicism will be assumed as the focal points for both Dewey’s (aesthetic) thinking and the epistemology of complexity
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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