Linearization of nonlinear connections on vector and affine bundles, and some applications

A linear connection is associated to a nonlinear connection on a vector bundle by a linearization procedure. Our definition is intrinsic in terms of vector fields on the bundle. For a connection on an affine bundle our procedure can be applied after homogenization and restriction. Several applications in Classical Mechanics are provided

A Solvable Model for Many Quark Systems in QCD Hamiltonians

Motivated by a canonical, QCD Hamiltonian we propose an effective Hamiltonian to represent an arbitrary number of quarks in hadronic bags. The structure of the effective Hamiltonian is discussed and the BCS-type solutions that may represent constituent quarks are presented. The single particle orbitals are chosen as 3-dimensional harmonic oscillators and we discuss a class of exact solutions that can be obtained when a subset of single-particle basis states is restricted to include a certain number of orbital excitations. The general problem, which includes all possible orbital states, can also be solved by combining analytical and numerical methods.Comment: 24 pages, 2 figures, research articl

On the improvement of the low energy neutrino factory

The low energy neutrino factory has been proposed as a very sensitive setup for future searches for CP violation and matter effects. Here we study how its performance is affected when the experimental specifications of the setup are varied. Most notably, we have considered the addition of the 'platinum' nu_{mu} -> nu_{e} channel. We find that, whilst theoretically the extra channel provides very useful complementary information and helps to lift degeneracies, its practical usefulness is lost when considering realistic background levels. Conversely, an increase in statistics in the 'golden' nu_{e} -> nu_{mu} channel and, to some extent, an improvement in the energy resolution, lead to an important increase in the performance of the facility, given the rich energy dependence of the 'golden' channel at these energies. We show that a low energy neutrino factory with a baseline of 1300 km, muon energy of 4.5 GeV, and either a 20 kton totally active scintillating detector or 100 kton liquid argon detector, can have outstanding sensitivity to the neutrino oscillation parameters theta13, delta and the mass hierarchy. For our estimated exposure of 2.8 x 10^{23} kton x decays per muon polarity, the low energy neutrino factory has sensitivity to theta13 and delta for sin^{2}(2theta13) > 10^{-4} and to the mass hierarchy for sin^{2}(2theta13) > 10^{-3}.Comment: 13 pages, 8 eps figures. Version published in PRD - experimental section with preliminary results removed, abstract and conclusions re-written accordingly, title changed, author list amended

Capital social, metas del milenio y desarrollo local : el caso de la Iniciativa de Carapeguá en Desarrollo, Paraguay

¿Puede lo global y lo local generar una sinergia catalizadora del desarrollo comunitario en forma sostenible? ¿Puede la aplicación de la "caja de herramientas" de la gerencia social fortalecer el capital social, que a su vez impulsará el desarrollo local? ¿Puede la capacitación en gerencia social ser un elemento articulador y catalizador del desarrollo local? El objetivo a corto plazo del programa fue el de fortalecer el capital social local para catalizar una estrategia de desarrollo local sostenible, que mejore las condiciones de vida de la población en forma consistente con los objetivos de desarrollo del milenio. Para evaluar el impacto del programa sobre el capital social, se presentan y analizan las acciones y procesos del programa que pudieron haber impactado sobre los distintos elementos que constituyen el acervo de capital social de una comunidad

Cerámica campaniforme de Galicia (NW de España): Caracterización arqueométrica y estudio de procedencia de algunos yacimientos representativos

Se describen los resultados del estudio arqueométrico (composición mineral y elemental) de 55 muestras de recipientes campaniformes recuperadas en 8 yacimientos arqueológicos del NW de la Península Ibérica. Las muestras son representativas de la variación formal de la cerámica (tanto lisa como decorada) y del tipo de contextos (ceremonial, doméstico y funerario) donde las cerámicas campaniformes fueron encontradas en la región. Las composiciones mineral y elemental mostraron un alto grado de coherencia. La mayor parte de los recipientes tenía composiciones con proporciones variables de feldespato potásico y plagioclasa, o de plagioclasa y anfíbol, coherentes con la litología local. También se encontraron composiciones mezcla de feldespato potásico y anfíbol, que no se encuentran de forma natural en los materiales geológicos del entorno, lo que apunta a una mezcla intencional de materias primas. La cerámica campaniforme, comparada con la de otros períodos previos, muestra fuertes cambios en relación con el estilo, pero mantiene una continuidad en cuanto al uso de los recursos de materia prima. No se encontró relación entre aspectos formales y la composición de la cerámica. La mayor parte de la cerámica estudiada procede probablemente del entorno de los yacimientos. Un análisis de distancias a las áreas potenciales para los materiales, empleando un sistema de información geográfica, sugiere que prácticamente todas pueden encontrarse en un radio de 16 km (la mayoría entre 2 y 5 km), lo que implica una a dos horas. Parece que el esfuerzo asociado a las cerámicas de contextos ceremoniales fue mayor que el de la cerámica de contextos funerarios y de asentamientoWe describe the results of an archaeometric study (mineral and elemental composition) of 55 samples from Bell Beaker vessels recovered from 8 archaeological sites in the northwest of the Iberian Peninsula. The samples are representative of the formal variation of the pottery (both decorated and undecorated) and type of contexts (ceremonial, domestic and funerary) in which Bell Beaker pottery is found in the region. Both, mineral and elemental composition were found to be highly consistent. Most of the vessels had compositions resulting from mixtures of potassium feldspar and plagioclase or plagioclase and amphibole, which are coherent with the local lithology. A few pottery samples showed a mixed composition of potassium feldspar and amphibole, which is not found naturally in the surrounding geological materials, indicating an intentional mixing of different raw materials. Compared to previous periods, Bell Beaker pottery represented a significant change in terms of style but continuity in terms of the use of raw materials. No relationship was found between the formal aspects and the composition of the pottery. Most of the samples we studied were probably manufactured with materials obtained from the area around the sites. An analysis of distances to potential source areas for the materials, using a geographical information system, indicates that almost all can be found within a radius of 16 km (most between 2-5 km), implying between one and two hours walk. A greater effort seems to have been associated to pottery of ceremonial sites compared to funerary and settlement sites

Mn valence instability in La2/3Ca1/3MnO3 thin films

A Mn valence instability on La2/3Ca1/3MnO3 thin films, grown on LaAlO3 (001)substrates is observed by x-ray absorption spectroscopy at the Mn L-edge and O K-edge. As-grown samples, in situ annealed at 800 C in oxygen, exhibit a Curie temperature well below that of the bulk material. Upon air exposure a reduction of the saturation magnetization, MS, of the films is detected. Simultaneously a Mn2+ spectral signature develops, in addition to the expected Mn3+ and Mn4+ contributions, which increases with time. The similarity of the spectral results obtained by total electron yield and fluorescence yield spectroscopy indicates that the location of the Mn valence anomalies is not confined to a narrow surface region of the film, but can extend throughout the whole thickness of the sample. High temperature annealing at 1000 C in air, immediately after growth, improves the magnetic and transport properties of such films towards the bulk values and the Mn2+ signature in the spectra does not appear. The Mn valence is then stable even to prolonged air exposure. We propose a mechanism for the Mn2+ ions formation and discuss the importance of these observations with respect to previous findings and production of thin films devices.Comment: Double space, 21 pages, 6 figure