1,721,315 research outputs found
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
Variability of the climatic antarctic system during the Plio-Pleistocene: Paleomagnetism contribution
No full textIn the framework of a gradual global warming, which is one of the topic of major interest in the recent years and which importance is resumed in the Intergovernmental Panel on Climate Change (IPCC), it is important the study of the variability of the Earth’s system at the high latitudes i.e., in Artic and Antarctic areas, because these are the regions more sensitive to climatic changes. The possibility to study marine sedimentary sequences from Antarctica thus represented an important opportunity to investigate such climatic variability. Cold water mass formation in the Southern Ocean is involved in the global thermohaline circulation (THC) through the convection and inter-ocean exchanges of surface, intermediate and bottom waters. This work focus on the study of marine sequences cores from mid-high latitudes from strategic locations far and near the continental margin of Antarctica: (1) ANTA 95-157 (62°05.95'S) and ANTA 96-16 (66°20.09'S) cores are a long transect from New Zealand and Ross Sea slightly south of the present day Polar Front and the Pacific Antarctic Ridge, respectively; (2) MD97-2114 (42°22.32'S) core is on the northern side of Chatham Rise, east of New Zealand; (3) ODP Site 1166 (67°41.77'S) and 1167 (66°24.01'S) are in Prydz Bay continental shelf and slope, respectively. It has been provided a detailed magnetostratigraphy of the sequences and have been investigated magnetic proxies, which reflect variations in mineralogy, grain-size, and concentration of the magnetic fraction. Environmental magnetic data, along with the chronology derived by the magnetostratigraphy, provided an important contribution to our understanding of environmental and climate changes during the time intervals here examined. The cores ANTA and MD97-2114 span the shift from predominant 41-ka to predominant 100-ka glaciation cycles at around 1.0–0.9 Ma, (the Mid-Pleistocene Climate Transition (MPT)) that was centered at 922±12 ka and lasted about 40±9 ka. The amplitude of the 100-ka cycle abruptly increased much later on, at 641±9 ka. The transition was accompanied by an increase in 18O and decrease in 13C but the causes may be many and further information about changes in global ice volume during this period needed. In this core it has been found evidence of orbital influence on sedimentary processes.
The core MD97-2114 records long-term variation of the upper Circumpolar Deep Water component of the Deep Western Boundary Current and manifests a stepwise modification of the THC during the transition. ODP Site 1166 and 1167 provide a record of the process involved in the story of the glacial expansion and retreat of the ice at the margin of the continent in Prydz Bay during the Plio-Pleistocene. Preliminary results from SEDANO cores shows downcore variations in concentration, mineralogy, and grain-size of magnetic minerals. In particular, there is a relative increase of moderate coercivity respect to low-coercivity minerals (magnetite) during glacials and a millennial scale variability of the magnetic grain size characterizes the last glacial (core SED 12 and 13) and it may be related to changes in the bottom current velocity.INGVUnpublished2.2. Laboratorio di paleomagnetismoreserve
Variability of the climatic antarctic system during the Plio-Pleistocene: Paleomagnetism contribution
No full textIn the framework of a gradual global warming, which is one of the topic of major interest in the recent years and which importance is resumed in the Intergovernmental Panel on Climate Change (IPCC), it is important the study of the variability of the Earth’s system at the high latitudes i.e., in Artic and Antarctic areas, because these are the regions more sensitive to climatic changes. The possibility to study marine sedimentary sequences from Antarctica thus represented an important opportunity to investigate such climatic variability. Cold water mass formation in the Southern Ocean is involved in the global thermohaline circulation (THC) through the convection and inter-ocean exchanges of surface, intermediate and bottom waters. This work focus on the study of marine sequences cores from mid-high latitudes from strategic locations far and near the continental margin of Antarctica: (1) ANTA 95-157 (62°05.95'S) and ANTA 96-16 (66°20.09'S) cores are a long transect from New Zealand and Ross Sea slightly south of the present day Polar Front and the Pacific Antarctic Ridge, respectively; (2) MD97-2114 (42°22.32'S) core is on the northern side of Chatham Rise, east of New Zealand; (3) ODP Site 1166 (67°41.77'S) and 1167 (66°24.01'S) are in Prydz Bay continental shelf and slope, respectively. It has been provided a detailed magnetostratigraphy of the sequences and have been investigated magnetic proxies, which reflect variations in mineralogy, grain-size, and concentration of the magnetic fraction. Environmental magnetic data, along with the chronology derived by the magnetostratigraphy, provided an important contribution to our understanding of environmental and climate changes during the time intervals here examined. The cores ANTA and MD97-2114 span the shift from predominant 41-ka to predominant 100-ka glaciation cycles at around 1.0–0.9 Ma, (the Mid-Pleistocene Climate Transition (MPT)) that was centered at 922±12 ka and lasted about 40±9 ka. The amplitude of the 100-ka cycle abruptly increased much later on, at 641±9 ka. The transition was accompanied by an increase in 18O and decrease in 13C but the causes may be many and further information about changes in global ice volume during this period needed. In this core it has been found evidence of orbital influence on sedimentary processes.
The core MD97-2114 records long-term variation of the upper Circumpolar Deep Water component of the Deep Western Boundary Current and manifests a stepwise modification of the THC during the transition. ODP Site 1166 and 1167 provide a record of the process involved in the story of the glacial expansion and retreat of the ice at the margin of the continent in Prydz Bay during the Plio-Pleistocene. Preliminary results from SEDANO cores shows downcore variations in concentration, mineralogy, and grain-size of magnetic minerals. In particular, there is a relative increase of moderate coercivity respect to low-coercivity minerals (magnetite) during glacials and a millennial scale variability of the magnetic grain size characterizes the last glacial (core SED 12 and 13) and it may be related to changes in the bottom current velocity.INGVUnpublished2.2. Laboratorio di paleomagnetismoreserve
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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Editorial: HPV and Host Interaction
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Editorial on the Research Topic HPV and Host Interactio
Natural Bioactives: Back to the Future in the Fight against Human Papillomavirus? A Narrative Review
Get PDFHuman papillomavirus (HPV) still represents an important threat to health worldwide. Better therapy in terms of further improvement of outcomes and attenuation of related side-effects is desirable. The pharmaceutical industry has always targeted natural substances—phytochemicals in particular—to identify lead compounds to be clinically validated and industrially produced as antiviral and anticancer drugs. In the field of HPV, numerous naturally occurring bioactives and dietary phytochemicals have been investigated as potentially valuable in vitro and in vivo. Interference with several pathways and improvement of the efficacy of chemotherapeutic agents have been demonstrated. Notably, some clinical trials have been conducted. Despite being endowed with general safety, these natural substances are in urgent need of further assessment to foresee their clinical exploitation. This review summarizes the basic research efforts conducted so far in the study of anti-HPV properties of bio-actives with insights into their mechanisms of action and highlights the variety of their natural origin in order to provide comprehensive mapping throughout the different sources. The clinical studies available are reported, as well, to highlight the need of uniformity and consistency of studies in the future to select those natural compounds that may be suited to clinical application
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