Future neutrino oscillation facilities

The recent discovery that neutrinos have masses opens a wide new field of experimentation. Accelerator-made neutrinos are essential in this program. Ideas for future facilities include high intensity muon neutrino beams from pion decay (`SuperBeam'), electron neutrino beams from nuclei decays (`Beta Beam'), or muon and electron neutrino beams from muon decay (`Neutrino Factory'), each associated with one or several options for detector systems. Each option offers synergetic possibilities, e.g. some of the detectors can be used for proton decay searches, while the Neutrino Factory is a first step towards muon colliders. A summary of the perceived virtues and shortcomings of the various options, and a number of open questions are presented.Comment: Originally written for the CERN Strategy Grou

Topology Classes of Flat U(1) Bundles and Diffeomorphic Covariant Representations of the Heisenberg Algebra

The general construction of self-adjoint configuration space representations of the Heisenberg algebra over an arbitrary manifold is considered. All such inequivalent representations are parametrised in terms of the topology classes of flat U(1) bundles over the configuration space manifold. In the case of Riemannian manifolds, these representations are also manifestly diffeomorphic covariant. The general discussion, illustrated by some simple examples in non relativistic quantum mechanics, is of particular relevance to systems whose configuration space is parametrised by curvilinear coordinates or is not simply connected, which thus include for instance the modular spaces of theories of non abelian gauge fields and gravity.Comment: 22 pages, no figures, plain LaTeX file; changes only in details of affiliation and financial suppor

From circular paths to elliptic orbits: A geometric approach to Kepler's motion

The hodograph, i.e. the path traced by a body in velocity space, was introduced by Hamilton in 1846 as an alternative for studying certain dynamical problems. The hodograph of the Kepler problem was then investigated and shown to be a circle, it was next used to investigate some other properties of the motion. We here propose a new method for tracing the hodograph and the corresponding configuration space orbit in Kepler's problem starting from the initial conditions given and trying to use no more than the methods of synthetic geometry in a sort of Newtonian approach. All of our geometric constructions require straight edge and compass only.Comment: 9 pages, 4 figure

Companion modelling for exploring natural resource management strategies in Palawanm, The Philippines

This paper reports experiences and lessons of a continuing study on the use of a contemporary analytical tool, Multi-agent Systems (MAS), to study the dynamics and complex interactions among stakeholders in the management of common renewable resources. In the MAS model, a renewable resource management system is represented with different autonomous entities, called agents, that are able to act, interact with other agents, and be affected by objects in the environment. In this study, the MAS model is developed using the Companion Modelling (ComMod) approach, a collaborative development of a MAS model between the stakeholders and researchers which places primary importance on the quality of process to ensure that the tools developed are acceptable and used with confidence. This approach involves the development and application of computer simulations and role-playing games (RPGs) to validate the MAS model as well as learn from it. Inferences are drawn from the learning and negotiation processes that the stakeholders and researchers undergo in the collaborative development of the MAS model and the techniques used to realize this model, i.e. computer simulation and RPG, as well as the development of a unified resource management plan for three villages. For the community, having acknowledged the RPG as a reliable representation of their reality, they see these tools as vehicles to reach the appropriate stakeholders and communicate their concerns about their livelihoods and resources. For local government agencies and non-government organizations, these tools serve as eye-openers about the dire livelihood conditions of the community. Furthermore, local governments see the RPG and computer simulation as effective techniques to inform and educate people about their plans or programs for the management of resources and livelihood for the community. The stakeholders also agree that these tools are useful in coming together and discussing issues pertaining to the management of their natural resources and livelihood activities. Given the benefits that could be derived from ComMod and MAS modelling in NRM, these techniques display a great potential in plantation management for increasing the financial returns

Fractura femoral en paciente portador de un clavo intramedular

Los autores presentan el caso de un paciente con una fractura femoral tratado con un clavo intramedular cerrojado que sufrió una nueva fractura antes de extraer el material de osteosíntesis.The authors present a patient with a femoral fracture treated by interlocking nail who underwent a new fracture of the femoral shaft before removal of the nail