7,063 research outputs found
Constraining Horava-Lifshitz gravity from neutrino speed experiments
We constrain Horava-Lifshitz gravity using the results of OPERA and ICARUS
neutrino speed experiments, which show that neutrinos are luminal particles,
examining the fermion propagation in the earth's gravitational field. In
particular, investigating the Dirac equation in the spherical solutions of the
theory, we find that the neutrinos feel an effective metric with respect to
which they might propagate superluminally. Therefore, demanding not to have
superluminal or subluminal motion we constrain the parameters of the theory.
Although the excluded parameter regions are very narrow, we find that the
detailed balance case lies in the excluded region.Comment: 5 pages, no figure, version published at Gen.Rel.Gra
Strategic Plan of the African Union Commission on Rural Economy and Agriculture
African agriculture and the rural economy suffer from low productivity, limited diversification and continuous degradation. Sustainable development of agriculture and the rural economy is critical for ensuring food security and poverty reduction in Africa. The African Union Commission considers the development of agriculture and the rural economy as a necessary condition for promoting accelerated economic, social and political development, and for attaining its shared vision of building an integrated, prosperous and peaceful Africa, an Africa driven and managed by its own citizens and representing a dynamic force in the international arena. The Directorate of Rural Economy and Agriculture (REA) is one of eight portfolio Directorates of the Commission given the mandate to initiate, promote and facilitate the implementation of policies, strategies and programs that can contribute to the transformation of the rural economy by increasing agricultural productivity, conserving and protecting natural resources as well as enhancing environmental sustainability. To more efficiently and effectively contribute to the AU Commissions vision, the REA Directorate has an elaborate strategic plan that will guide its actions over the next four years (2004-2007). The plan identifies the strategic objectives and outputs to be achieved and defines the activities and strategies for accomplishing the outputs. It envisages actions that address four strategic objectives through six program areas. Successful implementation of the plan, it is believed, will help create enabling conditions and facilitate actions to improve agricultural productivity, reduce food insecurity and rural poverty as well as to ensure sustainable management of natural resources and the environment.Community/Rural/Urban Development,
Gravity's Rainbow: a bridge towards Horava-Lifshitz gravity
We investigate the connection between Gravity's Rainbow and Horava-Lifshitz
gravity, since both theories incorporate a modification in the UltraViolet
regime which improves their quantum behavior at the cost of the Lorentz
invariance loss. In particular, extracting the Wheeler-De Witt equations of the
two theories in the case of Friedmann-Lemaitre-Robertson-Walker and spherically
symmetric geometries, we establish a correspondence that bridges them.Comment: 20 page
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