1,721,125 research outputs found
80. Carpanese L, Pizzi G, Golfieri R, Fiore F, Gasparini D (2006). A Phase II Clinical trial on hepatic intra-arterial injection of Yttrium-90 Microspheres in unresectable colorectal liver metastases refractory to standard i.v. chemotherapy. Preliminary results. Abstract First World Conference on Interventional Oncology (WCIO). Cernobbio, June 12-16, 2006
No full textPrestressing of 19th Century Wood and Iron Truss Bridges in the U.S.
No full textMany of the well-known American truss bridges built in the first half of the 19th century were prestressed. Specifically, the Long, Howe, Pratt and Rider/Moulton forms, built entirely of wood or iron or using a combination of wood and iron, were prestressed. The prestressing was achieved by driving wood or iron wedges or by tightening nuts on threaded iron rods. The level of prestressing was controlled only qualitatively, probably by observing if any elements became slack when a heavy live load traversed the span. The significant advantages of prestressing were that connections were simplified, some wood tensile connections were eliminated and, if all elements did not loosen, the stiffness of a bridge was increased.
This paper describes studies of the Eldean Bridge in Miami County, Ohio. The Eldean Bridge is a wooden Long truss, built in 1860 by James and William Hamilton. The experimental and analytical studies address the actual magnitudes of prestress forces achieved by driving wedges, the effects of prestress on the structural behavior, the loss of prestress from wood shrinkage and creep, and the need for periodic retightening. Also presented are studies of the Pine Bluff Bridge in Putnam County, Indiana. The Pine Bluff Bridge is a classic Howe truss, built in 1886 by Joseph Albert Britton. The studies quantify the actual magnitudes of prestress forces achieved by tightening nuts and examine the same issues as those for the Long truss.
After the Long and Howe trusses, two significant prestressed truss forms were patented in the U.S. They are the truss of Thomas and Caleb Pratt and the truss of Nathaniel Rider and Stephen Moulton. These designs are briefly discussed, to provide a more complete view of the early 19th century prestressed truss forms
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
Situated Breakdown Analysis for the Evaluation of a VirtualEnvironment
Full text linkIt is a widely-supported tenet in human-computer interaction that the meaningful unit of analysis is not the technical device alone, but the technical device together with the person interacting with it; the reason is that what is a relevant property of a technology is only understandable with respect to the specific goals and resources activated during its usage. This basic reflection should also inspire the procedure followed to evaluate the usability of a technology, namely its efficiency and satisfaction for a specific class of users. The topic of this paper is precisely to describe a method developed in compliance with this observation and aimed at evaluating the usability of virtual environments. Two main requirements were set forth: first, the method should take the strong connection between humans and technology as its building block, by linking a property of the virtual environment to a particular use that makes that property relevant. To this goal, action has been placed at the center of the analysis; the functional properties of the VE are then observed in the general economy of users’ interaction with the technology and the whole ensemble is the appropriate object of evaluation. Such ‘action-based’ approach (Gamberini, Spagnolli, 2002) is reminiscent of the Situated Action theory (Suchman, 1987) and Activity Theory (Nardi, 1996); the former proposes a detailed analysis of the sequential interaction with the technology and provides a rich examination of the structure given to it by the users. The latter focuses more on specific phenomena, such as contradictions and breakdowns, identified by the evaluators; it allows to profit from data poor in comments and verbalizations, and to analyze the interaction with the technology from a structural and organizational level. As a second requisite for the method, we wanted it to benefit from the advantages of both approaches; thus we decided to concentrate on the breakdowns occurring during users’ interaction with the VE but to study these episodes from a situated point of view. In our definition, breakdowns reveal an inappropriate interpretation of the possibilities for action offered by the virtual environment and are to be analyzed in their sequential, contextual unfolding. This version of breakdown analysis highlights the spontaneous, subjective problems in the use of a technology and connects them to specific aspects of users’ action. It renews the ergonomic tradition of error studies (Reason, 1990; Rasmussen, 1980) with an ethnographic contamination, that pays attention to users’ contextualized practices. It also suits the kind of data the interaction with a virtual environment is mostly made of, namely bodily action in a three-dimensional space. Few
methods with these characteristics have been employed so far to analyze the interaction with the VE. After a brief introduction, the paper will describe the basics of this approach and illustrate them with instances from the evaluation of a virtual librar
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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