1,721,151 research outputs found
Exploration of High Altitude Caves in the Baisun-Tau Mountain Range, Uzbekistan
No full textIn the late Eighties some Russian, Italian and British expeditions started the detailed exploration of the Baysun-Tau region,
a series of parallel limestone ranges showing karst features in an high altitude desert environment, with cave entrances
between 3,000 and 3,900 m a.s.l. The exploration came to a halt soon because of the breaking up of the Soviet Union and
related border contentions between Uzbekistan and Tagikistan. Over the past five years, the improvement of the political
situation in Uzbekistan and the possibility to get permits for exploration in this remote area has lead the Ekaterinburg
Speleological Club, with the support of La Venta Geographic Explorations, to inaugurate a new season of expeditions. In
two years, 2011–2012, new and extensive branches were explored in the cave systems Festivalnaya (-625 m, 16 km;
entrance at 3,500 m a.s.l.), Dark Star (-610 m, 7 km; entrance at 3,640 a.s.l.), with more than 11 km of new passages
surveyed. Dark Star, renamed as Central Karst System of Hodja Gur Gur Ata, in particular shows a great potential to
become one of the deepest caves of Central Asia, reaching now over 600 metres of depth but with a potential of 2,400
metres between the entrance and the resurgence of Machai. In 2011 also Ulugh Begh Cave was reached again, twenty
years after its first and unique exploration, discovering a new entrance at almost 3,800 m a.s.l. Additional to explorational
works, Chinese, Russian, and Swiss scientists harvested the first samples for climatic studies in 2012.
The Baysun Tau limestone ranges show exceptional potential not only for exploration and connection of the caves, but
also for future scientific research on paleo-climate and the paleo-geographic evolution of the area
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
Quantification of paleo-aquifer changes using clumped isotopes in subaqueous carbonate speleothems
Full text linkThis study was supported by the NERC project, ID NE/M003752/1 to D.A.H. The sampling surveys were supported by the Water Resources and Environmental Geology Research Group (University of Almería). S.F.M.B., F.G. and D.A.H. acknowledge support from the European Union's Horizon 2020 Research and Innovation programme for project “QUEST” (Marie Sklodowska-Curie grant agreement No. 691037). Usingle bondTh dating was supported by grants from Taiwan ROC MOST (104-2119-M-002-003, 105-2119-M-002-001 to C.-C.S.) and the Research Center for Future Earth, National Taiwan University (107L901001 to C.-C.S.).Here we track the water-table position and temperature of the Mount San Giovanni aquifer (Iglesiente-Sulcis mining district, SW Sardinia, Italy) during the past 600 ka by determining the ages (UTh dating) and stable isotope compositions (δ18O, δ13C and Δ47) of a variety of subaqueous carbonate speleothems (e.g. calcite spars, dogtooth calcite crystals and calcite coatings). Clumped isotopes (Δ47) provide quantitative estimates of carbonate formation temperatures (and thus water temperatures) that are independent of the oxygen isotope composition of water (δ18Ow). Then, the δ18Ow of the paleo-water has been reconstructed from the clumped isotope temperature (TΔ47) and the δ18O of the carbonate (δ18Oc). We find that high-temperature calcite spars formed already before 600 ka at temperatures above ~120 °C. Lower-temperature spars (~70 °C) precipitated at ~400 ka, and cold-water subaqueous speleothems (~10–20 °C) formed in perched ponds at different levels of the karst systems between 410 ka and 110 ka, while coeval precipitation of subaerial flowstones occurred in the upper levels of the shallower caves until 82 ka. We infer that the groundwater level dropped by ~120 m from ~400 to ~250 ka, with a relatively rapid rate of ~0.8 mm/y. Considering the tectonic stability of Sardinia during the Quaternary, this high rate derives from climate driven geomorphological processes at the surface rather than tectonic uplifting. The δ18O values of the paleo-aquifer water range from −6.0 ± 0.7‰ during MIS 5c, and similar to modern cave water values (−5.1‰), to −7.7± 0.4‰ during the colder MIS 8. These values indicate that the groundwater reflected the δ18O signal of meteoric water, with no significant contributions from metasomatism and metamorphic waters. The observed δ18Ow variability can be explained by glacial/interglacial paleoclimate changes affecting rainfall δ18O (and thus groundwater δ18O). We conclude that clumped isotope thermometry on subaqueous carbonate speleothems is a powerful tool for tracking paleo-aquifer temperatures and δ18Ow reconstructions.Peer reviewe
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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