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OBJECTIVE To estimate the occurrence and school-level clustering of drug involvement among school-attending adolescent youths in each of seven countries in Latin America, drawing upon evidence from the PACARDO research project, a multinational collaborative epidemiological research study. METHODS During 1999-2000, anonymous self-administered(More)
Web 2.0 tools have changed the relationship between users and libraries by improving the involvement of users in the libraries activities. To use such tools efficiently, it is essential to know if they are meeting user requirements and expectations, and how they could be improved to increase user satisfaction. The aim of this paper is to present a model to(More)
Citation classics identify those highly cited papers which are an important reference point in a research field. To identify a paper as a citation classic we have to fix a citation threshold value. Usually, this threshold value should not be the same for all research fields because each field presents its respective citation pattern. Studies of citation(More)
Objectives: This article reports the first science mapping analysis of the social work field, which shows its conceptual structure and scientific evolution. Methods: Science Mapping Analysis Software Tool, a bibliometric science mapping tool based on co-word analysis and h-index, is applied using a sample of 18,794 research articles published from 1930 to(More)
Water distribution networks are not randomly constituted systems. On the contrary, their designs are closely related to their hydraulic performance. Recognizing the sundry and relative importance of the different pipes in a water distribution network may help in assessing their impact on the hydraulic performance of the network. This information, in turn,(More)
We propose a methodological tool for examining the layout and revealing the concealed characteristics of urban water supply systems (WSS). For this purpose, we use underground images obtained with ground penetrating radar (GPR) as a method that does not alter the system conditions and environmental characteristics (non-destructive methods). The study(More)