41,656 research outputs found
Defending the Time Culture : The Public and Private Interests of Media Corporations
Part I of this essay discusses the âpublic interestâ standard under the Federal Communications Act and describes parallels in corporation doctrine. Part II considers whether broadcasters satisfy their public interest obligations by addressing audience interest. Part III discusses the prerogatives of the management of the corporate broadcaster to consider non-financial factors in selecting programming. Part IV describes the non-traditional philosophy of the corporation\u27s legitimate object, which led to the subject case. Part V discusses the central legal issues of the cognizable business interests of corporations. Finally, the Conclusion offers a view on desirable public interest objectives of media corporations
Sharks of the order Carcharhiniformes from the British Coniacian, Santonian and Campanian (Upper Cretaceous).
Bulk sampling of phosphate-rich horizons within the British Coniacian to Campanian (Upper Cretaceous) yielded very large samples of shark and ray teeth. All of these samples yielded teeth of diverse members of the Carcharhiniformes, which commonly dominate the fauna. The following species are recorded and described: Pseudoscyliorhinus reussi (Herman, 1977) comb. nov., Crassescyliorhinus germanicus (Herman, 1982) gen. nov., Scyliorhinus elongatus (Davis, 1887), Scyliorhinus brumarivulensis sp. nov., ? Palaeoscyllium sp., Prohaploblepharus riegrafi (MĂźller, 1989) gen. nov., ? Cretascyliorhinus sp., Scyliorhinidae inc. sedis 1, Scyliorhinidae inc. sedis 2, Pteroscyllium hermani sp. nov., Protoscyliorhinus sp., Leptocharias cretaceus sp. nov., Palaeogaleus havreensis Herman, 1977, Paratriakis subserratus sp. nov., Paratriakis tenuis sp. nov., Paratriakis sp. indet. and ? Loxodon sp. Taxa belonging to the families ?Proscylliidae, Leptochariidae, and Carcharhinidae are described from the Cretaceous for the first time. The evolutionary and palaeoecological implications of these newly recognised faunas are discussed
Shark and ray teeth from the Hauterivian (Lower Cretaceous) of north-east England
Sampling of hiatal horizons within the Hauterivian part of the Speeton Clay Formation of north-east England has produced teeth of several species of sharks and rays, four of which are previously unnamed. One species of shark, Cretorectolobus doylei sp. nov., and two species of rays, Spathobatis rugosus sp. nov. and Dasyatis speetonensis sp. nov., are named, whilst the presence of an indeterminate triakid shark is also noted. Synechodus dubrisiensis (Mackie) is shown to be a senior synonym of S. michaeli Thies. Although the dasyatid ray and triakid shark are by far the oldest representatives of their respective families, the overall composition of the fauna is considered to resemble more closely assemblages known from the Jurassic than those from upper parts of the Cretaceous
Libxc: a library of exchange and correlation functionals for density functional theory
The central quantity of density functional theory is the so-called
exchange-correlation functional. This quantity encompasses all non-trivial
many-body effects of the ground-state and has to be approximated in any
practical application of the theory. For the past 50 years, hundreds of such
approximations have appeared, with many successfully persisting in the
electronic structure community and literature. Here, we present a library that
contains routines to evaluate many of these functionals (around 180) and their
derivatives.Comment: 15 page
Dynamics of a family of piecewise-linear area-preserving plane maps I. Rational rotation numbers
This paper studies the behavior under iteration of the maps T_{ab}(x,y) =
(F_{ab}(x)-y,x) of the plane R^2, in which F_{ab}(x)=ax if x>=0 and bx if x<0.
The orbits under iteration correspond to solutions of the nonlinear difference
equation x_{n+2}= 1/2(a-b)|x_{n+1}| + 1/2(a+b)x_{n+1} - x_n. This family of
piecewise-linear maps has the parameter space (a,b)\in R^2. These maps are
area-preserving homeomorphisms of R^2 that map rays from the origin into rays
from the origin. The action on rays defines a map S_{ab} of the circle, which
has a well-defined rotation number. This paper characterizes the possible
behaviors of T_{ab} under iteration when the rotation number is rational. It
characterizes cases where the map T_{ab} is a periodic map.Comment: v2. original v1 (52 pages) divided in two parts, this is first part;
18 pages latex. Current part II is math.DS/0303007; part III is
math.DS/0505103 v3. revised to reflect prior work by Beardon, Bullett and
Rippon; v3 corrects misprint
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