University of Rennes

About: University of Rennes is a education organization based out in Rennes, France. It is known for research contribution in the topics: Population & Catalysis. The organization has 18404 authors who have published 40374 publications receiving 995327 citations.

Synthesis, fluorescence, and two-photon absorption of a series of elongated rodlike and banana-shaped quadrupolar fluorophores: a comprehensive study of structure-property relationships.

Abstract: An extensive series of push-push and pull-pull derivatives was prepared from the symmetrical functionalization of an ambivalent core with conjugated rods made from arylene-vinylene or arylene-ethynylene building blocks, bearing different acceptor or donor end-groups. Their absorption and photoluminescence, as well as their two-photon-absorption (TPA) properties in the near infrared (NIR) region, were systematically investigated to derive structure-property relationships and to lay the guidelines for both spectral tuning and amplification of molecular TPA in the target region. Whatever the nature of the core or of the connectors, push-push systems were found to be more efficient than pull-pull systems, and planarization of the core (fluorene versus biphenyl) always leads to an increase in the TPA cross sections. In contrast, increasing the conjugation length as well as replacement of a phenylene moiety by a thienylene moiety in the conjugated rods did not necessarily lead to increased TPA responses. The present study also demonstrated that the topology of the conjugated rods can dramatically influence the TPA properties. This is of particular interest in terms of molecular engineering for specific applications, as both TPA properties and photoluminescence characteristics can be considerably affected. Thus, it becomes possible to optimize the transparency/TPA and fluorescence/TPA efficiency trade-offs for optical limiting in the red-NIR region (700-900 nm) and for two-photon-excited fluorescence (TPEF) microscopy applications, respectively.

Participatory Cultural Mapping Based on Collective Behavior Data in Location-Based Social Networks

Abstract: Culture has been recognized as a driving impetus for human development. It co-evolves with both human belief and behavior. When studying culture, Cultural Mapping is a crucial tool to visualize different aspects of culture (e.g., religions and languages) from the perspectives of indigenous and local people. Existing cultural mapping approaches usually rely on large-scale survey data with respect to human beliefs, such as moral values. However, such a data collection method not only incurs a significant cost of both human resources and time, but also fails to capture human behavior, which massively reflects cultural information. In addition, it is practically difficult to collect large-scale human behavior data. Fortunately, with the recent boom in Location-Based Social Networks (LBSNs), a considerable number of users report their activities in LBSNs in a participatory manner, which provides us with an unprecedented opportunity to study large-scale user behavioral data. In this article, we propose a participatory cultural mapping approach based on collective behavior in LBSNs. First, we collect the participatory sensed user behavioral data from LBSNs. Second, since only local users are eligible for cultural mapping, we propose a progressive “home” location identification method to filter out ineligible users. Third, by extracting three key cultural features from daily activity, mobility, and linguistic perspectives, respectively, we propose a cultural clustering method to discover cultural clusters. Finally, we visualize the cultural clusters on the world map. Based on a real-world LBSN dataset, we experimentally validate our approach by conducting both qualitative and quantitative analysis on the generated cultural maps. The results show that our approach can subtly capture cultural features and generate representative cultural maps that correspond well with traditional cultural maps based on survey data.

Kinematics and Dynamics of Salt Tectonics Driven by Progradation

Abstract: Scaled physical models illustrate the importance of progradation as a trigger for salt tectonics and formation of allochthonous sheets. Regional extension and contraction were excluded in the models. In our experiments, prograding wedges above a tabular, buoyant salt layer with a flat base expelled the salt basinward, forming the following structures proximally to distally: (1) sigmoidally distorted initially planar wedges, (2) relict salt pillows and salt welds, (3) basinward-dipping expulsion rollover and crestal graben, (4) rollover syncline, (5) landward-facing salt-cored monocline, and (6) distal inflated salt layer. This deformation zone amplified and advanced basinward during progradation; however, no diapiric salt structures formed. Over a buoyant salt layer whose basement had steps facing landward, progradation initially formed a broad anticline where salt flow was restricted across each basement step. Distal aggradation pinned the anticline and enhanced differential loading. The anticline actively pierced its crest, which ©Copyright 1997. The American Association of Petroleum Geologists. All rights reserved.1Manuscript received October 2, 1995; revised manuscript received May 9, 1996; final acceptance October 16, 1996. 2Bureau of Economic Geology, University of Texas at Austin, and Department of Geological Sciences, University of Texas at Austin, Austin, Texas 78713. 3Bureau of Economic Geology, University of Texas at Austin, Austin, Texas 78713. All modeling was done at the Applied Geodynamics Laboratory of the Bureau of Economic Geology, with financial support by grant number 3658-178 from the Texas Advanced Technology Program and from the following companies: Agip S.p.A, Amoco Production Company, Anadarko Petroleum Corporation, ARCO Exploration and Production Technology, BP Exploration, Chevron Petroleum Technology Company, Conoco and Dupont, Exxon Production Research Company, Louisiana Land and Exploration Company, Marathon Oil Company, Mobil Research and Development Corporation, Petroleo Brasileiro S.A., Phillips Petroleum Company, Societe Nationale Elf Aquitaine Production, Statoil, Texaco, and Total Minatome Corporation. The Department of Geological Sciences and the Geology Foundation at the University of Texas at Austin and Phillips Petroleum Company provided additional financial support for Hongxing Ge. Dan Schultz-Ela helped us depth convert and restore seismic sections. Mark Rowan, Mike Hudec, Lee Fairchild, Sharon Mosher, and Tucker Hentz provided invaluable suggestions for improving the paper. Publication authorized by the Director, Bureau of Economic Geology, University of Texas at Austin.