Canalización mediática ("agenda-setting") y elecciones en Estados Unidos.

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Periodismo y nuevas tecnologías: Perfiles de los periodistas del siglo XXI.

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Photoemission studies of the γ−α phase transition in Ce: Changes in 4f character

Photoemission studies of the γ−α phase transition in cerium show changes in two 4f-related features in the valence band (0.3 and 2 eV below EF) and broadening of the multiplet structure in the region of the 4d−4f transitions. We show that the observed features can be explained by increased hybridization of the 4f wave function upon entering the α phase

Canalización mediática ("agenda-setting") y elecciones en Estados Unidos.

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Low-energy interband absorption in bcc Fe and hcp Co

We have examined the electronic structure of bcc Fe and single-crystal hcp Co by using optical absorptivity and thermoreflectance techniques for 0.2≤hν≤5 eV. The optical conductivities σ were calculated by Kramers-Kronig analyses. A prominent structure was observed in σ for Fe at 2.37 eV and a shoulder was observed near 0.8 eV; the latter structure was the dominant feature in the thermoreflectance spectrum. These were discussed in terms of minority-spin band interband absorption and spin-flip interband transitions. The anisotropic optical conductivities of hcp Co were discussed in terms of recent energy-band calculations

High velocity spikes in Gowdy spacetimes

We study the behavior of spiky features in Gowdy spacetimes. Spikes with velocity initially high are, generally, driven to low velocity. Let n be any integer greater than or equal to 1. If the initial velocity of an upward pointing spike is between 4n-3 and 4n-1 the spike persists with final velocity between 1 and 2, while if the initial velocity is between 4n-1 and 4n+1, the spiky feature eventually disappears. For downward pointing spikes the analogous rule is that spikes with initial velocity between 4n-4 and 4n-2 persist with final velocity between 0 and 1, while spikes with initial velocity between 4n-2 and 4n eventually disappear.Comment: discussion of constraints added. Accepted for publication in Phys. Rev.