403 research outputs found
Gamma-ray triangles: a possible signature of asymmetric dark matter in indirect searches
We introduce a new type of gamma-ray spectral feature, which we denominate
gamma-ray triangle. This spectral feature arises in scenarios where dark matter
self-annihilates via a chiral interaction into two Dirac fermions, which
subsequently decay in flight into another fermion and a photon. The resulting
photon spectrum resembles a sharp triangle and can be readily searched for in
the gamma-ray sky. Using data from the Fermi-LAT and H.E.S.S. instruments, we
find no evidence for such spectral feature and therefore set strong upper
bounds on the corresponding annihilation cross section. A concrete realization
of a scenario yielding gamma-ray triangles consists of an asymmetric dark
matter model where the dark matter particle carries lepton number. We show
explicitly that this class of models can lead to intense gamma-ray spectral
features, potentially at the reach of upcoming gamma-ray telescopes, opening a
new window to explore asymmetric dark matter through indirect searches.Comment: 11 pages, 6 figures. Published versio
On the Lagrange and Markov Dynamical Spectra for Geodesic Flows in Surfaces with Negative Curvature
We consider the Lagrange and the Markov dynamical spectra associated to a
geodesic flow on a surface of negative curvature. We show that for a large set
of real functions on the unit tangent bundle and for typical metrics with
negative curvature and finite volume, both the Lagrange and the Markov
dynamical spectra have non-empty interior
El impacto de la crisis en el uso y aprovechamiento de las TIC en las televisiones regionales públicas en España, Francia, Italia y Reino Unido
La presente investigación se interesa en evaluar la manera en que las televisiones regionales públicas de España, Francia, Italia y Reino Unido han generado, adoptado y explotado la tecnología entre 2007 y 2012, años en los que un escenario de crisis económica ha asolado a la economía europea. Con el interés de realizar una valoración diferencial de los indicadores seleccionados se procedió a la construcción del indicador sintético. La conclusión general que se desprende del trabajo empírico señala que los casos de los entes regionales públicos del Reino Unido y Francia la crisis no ha evidenciado efectos muy nocivos, mientras que, ciertamente, en los casos de los entes Italianos y Españoles es plenamente constatable
Anticipatory responsible innovation: Futures construction in the face of the techno-economic imperative
The call for the development of more responsible research and innovation has increasingly permeated European Union research and development policies. Specifically, under the auspices of approaches such as “Responsible Research and Innovation” (RRI) and “Open Science”, these policies conceive of the need to make innovation dynamics radically open and debatable, even with regard to the underlying preferences and expectations shaping them. Responsibility has thus been conceived in eminently anticipatory terms, that is, in terms of collectively taking care in the present of the futures enabled through innovation practices. This normative conception, which emphasises the politicisation of the ways futures are constructed through innovation and goals they are oriented towards, is nonetheless realised within a context where the prevailing way of approaching the future with regard to innovation systems is highly committed to a capitalist imperative of technological progress and economic growth. This article argues that while anticipation – understood as an interventive practice – can deploy valuable responsibilisation heuristics, their degree of disruptiveness, or openness, may depend on how such interventive practice engaging with futures deals with this techno-economic commitment, or imperative
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