1,721,116 research outputs found
Cell cycle and cancer
No full textPurpose: To evaluate the link between cell cycle dysfunctions and tumor formation. Design: A review of the cell cycle mechanism and its regulatory factors which are involved in carcinogenesis. Result: Cell duplication is directed by a precise cellular machine. The engine of this machine is composed of the cyclin-dependent kinases (Cdks). Their function mainly consists of phosphorylating the pRb family of proteins to conduct the cell towards a series of events that end in generating two sister cells from one mother cell. The regulation of Cdk activity depends on several cellular proteins that are part of a major system that is able to sense extracellular factors and intracellular signals. Abnormalities in cell cycle regulation and in its checkpoints lead to development of malignant cells. Various components of the cell cycle machinery are mutated, overexpressed or eliminated in several human cancers. Some of them can be even classified as oncogenes or tumor suppressor genes. Conclusions: It is necessary to design new antitumoral strategies able to target cells harboring such alterations, in order to understand the events that regulate the cell cycle and its disruption during oncogenesis
RILIEVI LASER DELLA CUPOLA DEL BATTISTERO DEI SANTI GIOVANNI E REPARATA A LUCCA A SUPPORTO DELLO STUDIO STATICO
No full textTerrestrial Laser Scanning as road’s Cadastre revision and integration support
No full textTopography and Photogrammetric Section of Civil Engineering Department of University of Pisa, in cooperation with Centre of Excellence TeleGeomatics of University of Trieste, is experimenting laser data’s integration with collected data by MMS (Mobile Mapping System) vehicles. That vehicles are being used by the two research centres on road’s cadastre. Two different laser scanners are used for experiments, the Riegl LMS-Z210i and the Optec ILRIS-3D. The survey concern different kinds of road’s elements and a pair of road’s intersections. Test have been carried out aiming at the review the potential and productivity of laser use in comparison with classic survey’s technique. Some examples of data collection and processing are described. Survey are realised both with instruments on the ground both with laser located on top of VINCI’S (Vehicle Vehicle-borne Integrated Navigation and Cartographic Information Prime System), the MMS vehicle of University of Pisa
Physiological role of root surface phosphatases in adaptation strategies of Alyssum bertolonii Desv. to serpentine edaphic conditions.
No full textRoot surface phosphatase activity and P nutrition in the presence of Ni2+ was studied in Alyssum bertolonii DESV., a Ni-accumulating species of Tuscan serpentine soils. Increasing external concentrations of inorganic phosphate reduced phosphatase activity. In the presence of an inhibiting concentration of inorganic phosphate, Ni2+ stimulated phosphatase activity of seedlings treated for seven days but did not affect root P content. Root surface phosphatase showed a higher activity towards phytate in comparison with other P organic substrates. Increased P levels were detected in the roots of Ni-treated seedlings supplied with phytate. We discuss the possible physiological role of root cell wall phosphatases, which in this study was shown to be tolerant to Ni2+
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
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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