The weight of matter

Einstein's traceless 1919 gravitational theory is analyzed from a variational viewpoint. It is shown to be equivalent to a transverse (invariant only under diffeomorphisms that preserve the Lebesgue measure) theory, with an additional Weyl symmetry, in which the gauge is partially fixed so that the metric becomes unimodular. In spite of the fact that this symmetry forbids direct coupling of the potential energy with the gravitational sector, the equivalence principle is recovered in the unimodular gauge owing to Bianchi's identities.Comment: LaTeX, 11 page

Few-body decay and recombination in nuclear astrophysics

Three-body continuum problems are investigated for light nuclei of astrophysical relevance. We focus on three-body decays of resonances or recombination via resonances or the continuum background. The concepts of widths, decay mechanisms and dynamic evolution are discussed. We also discuss results for the triple $\alpha$ decay in connection with $2^+$ resonances and density and temperature dependence rates of recombination into light nuclei from $\alpha$-particles and neutrons.Comment: 9 pages, 8 figures. Proceedings of the 21st European Few Body Conference held in Salamanca (Spain) in August-September 201

Modeling the thermal behavior of biosphere 2 in a non-controlled environment using bond graphs

Biosphere 2 is a closed ecological system of high complexity built to deepen the understanding of ecological systems, to study the dynamics of closed ecologies, and to learn to control their behavior. The use of modeling and simulation is crucial in the achievement of these goals. Understanding a physical system is almost synonymous with possessing a model of its comportment. The main goal of this study is the development of a dynamic bond graph model that represents the thermal behavior of the complex ecological system under study, Biosphere 2. In this work, a first model that captures the behavior of the ecological system in a non-controlled environment is presented.Postprint (published version

A Change of Variables to the Dual and Factorization of Composite Anomalous Jacobians

Changes of variables giving the dual model are constructed explicitly for sigma-models without isotropy. In particular, the jacobian is calculated to give the known results. The global aspects of the abelian case as well as some of those of the cases where the isometry group is simply connected are considered. Considering the anomalous case, we infer by a consistency argument that the `multiplicative anomaly' should be replaceable by adequate rules for factorization of composite jacobians. These rules are then generalized in a simple way for composite jacobians defined in spaces of different types. Implimentation of these rules then gives specific formulas for the anomally for semisimple algebras and also for solvable ones.Comment: 15 pages, no figures, Latex file, A treatment of the global aspects of the abelian and of semisimple duality groups are added. General formulas for the mixed anomaly are derive

Softly Broken N=2 QCD with Massive Quark Hypermultiplets, I

We present a general analysis of all the possible soft breakings of N=2 supersymmetric QCD, preserving the analytic properties of the Seiberg-Witten solutions for the SU(2) group with Nf=1, 2, 3 hypermultiplets. We obtain all the couplings of the spurion fields in terms of properties of the Seiberg-Witten periods, which we express in terms of elementary elliptic functions by uniformizing the elliptic curves associated to each number of flavors. We analyze in detail the monodromy properties of the softly broken theory, and obtain them by a particular embedding into a pure gauge theory with higher rank group. This allows to write explicit expressions of the effective potential, which are close to the exact answer for moderate values of the supersymmetry breaking parameters. The vacuum structures and phases of the broken theories will be analyzed in the forthcoming second part of this paper.Comment: 35 pages, 3 figures, LaTeX file. Minor corrections in a few formulae, typos correcte

Rudiments of Holography

An elementary introduction to Maldacena's AdS/CFT correspondence is given, with some emphasis in the Fefferman-Graham construction. This is based on lectures given by one of us (E.A.) at the Universidad Autonoma de Madrid.Comment: 60 pages, additional misprints corrected, references adde

Recursos gemorfológicos: evolución morfológica de las marmitas de erosión en el río Miño

5 páginas, 4 figuras.-- VII Simpósio Ibérico sobre a Bacia Hidrográfica do Rio Minho, Vilanova de Cerveira, 7-8 novembro 2014En el río Miño, que discurre en su mayor parte sobre granitos, se distinguen zonas en las que la corriente circula directamente sobre la roca madre con formas características de erosión fluvial. Una de las más comunes son las marmitas (potholes) que se van a generar en condiciones dependientes del régimen hídrico y la estacionalidad del flujo del río. Junto a otras formas, las marmitas son parte del patrimonio geomorfológico fluvial asociado al río Miño. En este estudio se presenta una secuenciación evolutiva diferenciada en cuatro fases, para las cuales se han establecido valores umbral que marcan cambios en la morfologíaPeer reviewe

Growth of sculpted forms in bedrock channels (Miño River, northwest Spain)

7 páginas, 4 tablas, 6 figurasA total of 216 sculpted forms were registered on the granitic bedrock of the Miño River, northwest Iberian Peninsula. Analysis of in situ measurements (length, width and depth) revealed three general type-sets: incipient forms, longitudinal furrows and circular pot-holes. Maximum depth and upper radius (at the incision surface) were identified as key variables to mathematically determine the growth rate in each set. Three regression models are presented revealing that the development of the forms depends on a power law explaining their size and shape. Morphological and dimensional thresholds were established to better identify stages from incipient active growth) and inherited (stationary growth) formsM.A.A.V. is supported by the Xunta de Galicia through the Plan Galego de investigación, innovación e crecemento 2011-2015 (Plan I2C) in collaboration with the International Campus do Mar (Predoc ED481A-2015/410)Peer reviewe