1,721,020 research outputs found
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
On the Distance Between CP-nets
No full textPreferences play a key role in decision making by both single individuals and/or groups.
In a multi-agent context, it is also important to know how to aggregate preferences to reach a collective decision.
Moreover, being able to measure the distance between the preference of two individuals is important to
identify the amount of disagreement and possibly reach consensus.
In this paper we define a notion of distance between CP-nets, a formalism that can compactly encode conditional qualitative preferences. We consider the Kendall-tau distance between the partial orders induced by CP-nets,
and we define two tractable approximations of that distance, which can be computed in time polynomial
in the number of features of the CP-nets.
We then perform experiments to demonstrate the quality of these approximations compared to the Kendall-tau distance.
We also relate our two notions of distance to the distance rationalizability of sequential plurality voting for CP-nets
Contaminants in the environment. A multidisciplinary Assessment of Risks to Man and Other Organisms
No full textThe Summer School' 'Multidisciplinary Assessment of Environmental Risks for Human
Health" focused on human health hazards presented by contaminants with the major emphasis on direct effects. However, there are also indirect effects of contaminants that are or may be detrimental to mankind. Contaminants can have damaging effects on aquatic organisms such as fish and small molluscs, which are important sources of food-especially in third-world countries.
Also, the injudicious use of insecticides has sometimes led to outbreaks of pest infestation, causing damage to crops, as a consequence of the decimation of natural predators or parasites. Thus, the program of the Summer School has also included certain presentations on ecotoxicological issues that have relevance to the main theme of the course.
The School gave attention to disparate aspects of the problem of risk assessment-from the molecular mechanisms that underly toxicity to the practical and administrative issues of environmental management. The basis scientific issues of environmental toxicology apply to all animals. In considering them, no distinction has been made between man and other animals. Indeed, most of the scientific work has involved the use of laboratory animals acting as surrogates for man.
Thus the first three sections of the book deal mainly with principles that are relevant to living organisms generally. The fourth section, however, deals specifically with the question of risks for human health. The final section deals with environmental management in a broad way, touching on issues relevant to both the "human environment" and the "natural environment." The individual sections will now be considered in a little more detail.
Section I is concerned with the distribution and fate of contaminants. It includes a chapter dealing with models that may be used to predict the distribution of chemicals in the global environment. Two other chapters discuss approaches to the problem of monitoring. A more specialized chapter deals with one of the most serious problems encountered in environmental toxicology - the biomagnification of persistent contaminants in marine food chains.
Section II focuses on the relationship between metabolism and toxicity. This is fundamental to an understanding of the scientific basis of selective toxicity. An important practical aspect of this is the suitability of animal models for humans in toxicity testing. A better understanding of the metabolic regulation of toxicity should lead to the employment of better models for predicting toxicity to man. Although metabolism of contaminants is usually associated with detoxification, there are important exceptions to this rule. Some carcinogens and some highly toxic organophosphorus insecticides are activated by metabolism. These issues are brought out by contributors to this section.
Section III deals with toxic effects of contaminants. Clearly in the present text, it would not be appropriate to attempt a comprehensive view of the subject. Instead only a few selected examples are given, and emphasis is placed on the question of biomarkers. Until now, much of the work on environmental contamination has been concerned only with the measurement of levels of chemicals. Seldom has it been possible to say anything about the consequent effects.
Taken alone, data on residue levels are of little assistance in reaching decisions about the control of environmental chemicals. A major purpose of the development of biomarkers is to overcome this problem-to provide measures of harmful effects of chemicals in the environment, thus giving a firm scientific basis for policy decisions on pollution control.
Section IV is concerned with the question of effects of contaminants on human health. With eight chapters, this is the largest section in the book, in keeping with the particular focus of the School. General issues such as environmental epidemiology and fate of inhaled substances are dealt with here, but the main focus is on the human health risks presented by specific compounds.
Section V concludes the text by focusing on issues of environmental management. These
include valuable contributions on the policy of International Organizations concerned with pollution.
Regarding the overall book, it should be stressed that this is a collection of articles by authorities in specific fields. It focuses on specific issues, within a wide framework. It is hoped that this will provide valuable reading to students attending the Summer School at Siena in the future, and also to others following courses in environmental toxicology elsewhere. Finally it may also be of value
to interested lay people having a scientific background
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