1,720,961 research outputs found
The A.D. 472 eruption of the Somma volcano
No full textThe results of a detailed quantitative and statistical analysis on benthic foraminiferal assemblages from the Langhian Cretaccio composite section cropping out at Tremiti Islands (southern Adriatic Sea, eastern Mediterranean Sea) are presented. The distribution patterns of the species allowed us to estimate a paleodepth of about 600 m for the entire composite section. The abundance curve of the oxic species indicates relatively well-oxygenated conditions of bottom water masses with a weak but gradual decline which culminates at about 37-38 m after the First Occurrence (FO) of Orbulina suturalis. The discontinuous distribution of Cibicidoides wuellerstorfi is suggested to be indicative of alternating episodes of active and relatively sluggish circulation of bottom water masses. Two major changes in the benthic foraminiferal assemblages are recorded along the succession. The first one occurring in correspondence of the lithological colour change at about 15 m is characterized by the sharp decrease of Bulimina costata, Gyroidina spp., Hanzawaia boueana and Melonis barleeanum testifying a decrease in productivity. The second one is more gradual and it is characterized by the regular increase of Uvigerina semiornata and U. striatissima/rom 8 m to 37-38 m indicating a gradual change in oxygen content. A third, less pronounced change concerns the last meters of the section, suggesting an amelioration of the bottom conditions. These changes are interpreted as the first response to paleoceanographic variations related to the closure of the connections between Tethyan and Indo-Pacific water masses. In term of chronology the section is estimated spanning the interval preceding the Paracme End (PE) of Sphenolithus heteromorphus (estimated approximately at 15.65 Ma) and postdating the FO of O. universa (dated at 14.36 Ma)
The A.D. 79 eruption as a future explosive scenario in the Vesuvian area: evaluation of associated risk.
No full text5-aminolaevulinic acid/Photo-Dynamic Therapy and Gefitinib in Non Small Cell Lung Cancer cell lines: a potential strategy to improve Gefitinib therapeutic efficacy
No full textAbstract
OBJECTIVES:
Often, non-small cell lung cancers (NSCLC) respond only poorly to the tyrosine kinase inhibitor (TKI) gefitinib, which targets the epidermal growth factor receptor (EGFR), these poor responders EGFRs lacking activating mutations. In this study, we have attempted to improve TKI response of NSCLC cell lines (A549 and H1299) devoid of EGFR mutations, by combination of gefitinib and 5-ALA/photodynamic therapy (PDT).
MATERIALS AND METHODS:
Cells of the two lines were incubated with gefitinib (from 0.5 to 50 mm, for 48 h) then irradiated at doses ranging from 4 to 20 J/cm(2) ; 5-ALA concentration and incubation time were kept constant (1 mm for 3 h). We analysed cell viability, colony-forming efficiency, cell cycle parameters, proteasome and NF-??B activity and expression patterns of specific proteins, after individual or combined treatments.
RESULTS:
Effects (antagonistic, additive or synergistic) of combination treatment were evaluated using a predictive model (combination index) for expected interactive effects and results are consistent with mutual potentiation exceeding simple additivity. Investigation of molecular mechanisms underlying cytotoxic effects indicated that combination treatment impaired proteasome function, inhibited NF-??B transcriptional activity and hampered AKT pro-survival signalling.
CONCLUSIONS:
The results of this study show that poor response of cells devoid of EGFR activating mutations to TKIs, can be overcome by combining gefitinib with 5-ALA/photodynamic therapy (PDT)
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
The A.D. 79 eruption as a future explosive scenario in the Vesuvian area: evaluation of associated risk.
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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