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Apatite (U-Th)/He and fission track thermochronometry have been combined with 3D thermal modelling to constrain the late-to post-orogenic exhumation history of the Central Pyrenees, Spain. Data from four masifs immediately north and south of the present drainage divide of the mountain belt reveal a diachroneity in the transition from syn-to post-orogenic forcing of exhumation. Immediately south of the drainage divide, rapid exhumation of ~1.5mm year-1 decelerated after ~30Ma to ~0.03 mm year -1. A similar transition occured immediately north of the drainage divide at the same time. Further south, in the core of the Axial Zone antiformal stack of the Pyrenees, rapid (~1mm year-1), syn-orogenic exhumation continued to ~20Ma, but slowed to ~0.1-0.2 mm year-1 soon after that time. This order of magnitude decrease in exhumation rates a...
Using data from 1959-98, this study examines the impact of legislative television (C-SPAN2) on the number of filibusters in the United States Senate. As previous work has suggested, the institutional rules of the federal legislative branch of government in the U.S. often allow for political grandstanding and posturing, and these activities are enhanced with the presence of television cameras on the legislative floor. Like those previous studies, the present work builds a theoretical model wherein political services are considered search/experience goods, and service providers (federal legislators) are expected utility maximizers who are concerned with promoting their policy preferences and their re-election prospects. Poisson model estimates suggest that the presence of legislative television has worked to increase the filibuster count...
Comment: 16 pages, LaTeX, uses FeynTeX package for figures
Comment: 16 pages, 2 figures. Figures use FeynTeX package.Minor modifications made. Version to appear in Phys.Lett. B
(Figure Presented) Post-polymerization modification is based on the direct polymerization or copolymerization of monomers bearing chemoselective handles that are inert towards the polymerization conditions but can be quantitatively converted in a subsequent step into a broad range of other functional groups. The success of this method is based on the excellent conversions achievable under mild conditions, the excellent functional-group tolerance, and the orthogonality of the post-polymerization modification reactions. This Review surveys different classes of reactive polymer precursors bearing chemoselective handles and discusses issues related to the preparation of these reactive polymers by direct polymerization of appropriately functionalized monomers as well as the post-polymerization modification of these precursors into functiona...
When members of society cannot access the World Wide Web, or the information and services it contains in a meaningful or useful way, they can become digitally excluded. Many factors have been highlighted as having an effect on the likelihood of exclusion, including psychological, material and skills related barriers. In this paper, we consider the role played by authentication systems in the divide. In light of the widely researched tension between aspects of usability and security in authentication, we identify a number of conflicting accessibility and security goals as manifested in image and sound based schemes.
The modern world increasingly requires us to prove our identity. When this has to be done remotely, as is the case when people make use of web sites, the most popular technique is the password. Unfortunately the profusion of web sites and the associated passwords reduces their efficacy and puts severe strain on users’ limited cognitive resources. There is clearly a need for some creativity in terms of providing viable alternatives to passwords. This paper reports experiences of the use of a musical password, one composed of melodies instead of alphanumerics. Music is universal all over the globe and humans have superior memory for music. We report here on the evaluation of a prototype of such a musical password system, which demonstrates superior memorability and acceptance by users and is particularly useful to those with impa...
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