International audienceThis paper shows by a constructive method the existence of a diagrammatic representation called extended Euler diagrams for any collection of sets X1, ..., Xn , n < 9. These diagrams are adapted for representing sets inclusions and intersections: each set Xi and each non empty intersection of a subcollection of X1, ..., Xn is represented by a unique connected region of the plane. Starting with an abstract description of the diagram, we define the dual graph G and reason with the properties of this graph to build a planar representation of the X1, ..., Xn. These diagrams will be used to visualize the results of a complex request on any indexed video databases. In fact, such a representation allows the user to perceive simultaneously the results of his query and the relevance of the database according to the query

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News production requires investment, and competitors' ability to appropriate a story may reduce a media's incentives to provide original content. Yet, there is little legal protection of intellectual property rights in online news production, which raises the issue of the extent of copying online and the incentives to provide original content. In this article, we build a unique dataset combining all the online content produced by French news media during the year 2013 with new micro audience data. We develop a topic detection algorithm that identifies each news event, trace the timeline of each story, and study news propagation. We provide new evidence on online news production. First, we document high reactivity of online media: one quarter of the news stories are reproduced online in under 4 min. We show that this is accompanied by substantial copying, both at the extensive and at the intensive margins, which may constitute a severe threat to the commercial viability of the news media. Next, we estimate the returns to originality in online news production. Using article-level variations and media-level daily audience combined with articlelevel social media statistics, we find that original content producers tend to receive more viewers, thereby mitigating the newsgathering incentive problem raised by copying.

News production requires investment, and competitors’ ability to appropriate a story may reduce a media’s incentives to provide original content. Yet, there is little legal protection of intellectual property rights in online news production, which raises the issue of the extent of copying online and the incentives to provide original content. In this article, we build a unique dataset combining all the online content produced by French news media during the year 2013 with new micro audience data. We develop a topic detection algorithm that identifies each news event, trace the timeline of each story, and study news propagation. We provide new evidence on online news production. First, we document high reactivity of online media: one quarter of the news stories are reproduced online in under 4 min. We show that this is accompanied by substantial copying, both at the extensive and at the intensive margins, which may constitute a severe threat to the commercial viability of the news media. Next, we estimate the returns to originality in online news production. Using article-level variations and media-level daily audience combined with article-level social media statistics, we find that original content producers tend to receive more viewers, thereby mitigating the newsgathering incentive problem raised by copying.

International audienceIn this paper, we present a new graphical interface for traditional library environments, which allows the user to elaborate easily and efficiently new strategies in search processes. This tool is based on two linked interactive Euler diagram representations. The first one is an interactive representation of the structures composing the documentary kernel of the library. The user may navigate and select items, making their own understanding of the database content, structure and access. The second one is a set based visualization of the results of a composed query. This allows the user to validate his search context and to elaborate strategies to go through the results. The association of both interfaces generates a tool that allows the user to elaborate the main search strategies through graphical manipulations