Financing schemes for residential, grid-connected PV solar systems in BCS, Mexico

This article presents two proposals to spur the extensive adoption of grid-connected, residential, solar photovoltaic systems in the Mexican state of Baja California Sur. To this aim, electricity generation costs and subsidies were estimated first, together with time-of-generation avoided costs that could result from the implementation of such solar systems. An overview of financing mechanisms for solar and other renewable energies around the world is also presented followed by current mechanisms available in Mexico. The first proposal is centered around the operation of a solar energy service company that would receive the avoided cost of generation as compensation in return for sourcing, installing, and maintaining solar PV systems on residential users’ roofs. This would free up the residential user from any future electricity payments. The second proposal consists in the implementation of a feed-in tariff (FiT), currently unavailable in Mexico for residential users. The FiT could be funded from the avoided generation cost in conventional plants plus the corresponding savings from self-generation of electricity. Alternatively, the option of funding the FiT from small increases in electricity prices to all customers was also explored. Present value analyses suggest that both proposals are worthwhile pursuing in Baja California Sur

Parameter constraints for high-energy models of colliding winds of massive stars: the case WR 147

We explore the ability of high energy observations to constrain orbital parameters of long period massive binary systems by means of an inverse Compton model acting in colliding wind environments. This is particular relevant for (very) long period binaries where orbital parameters are often poorly known from conventional methods, as is the case e.g. for the Wolf-Rayet (WR) star binary system WR 147 where INTEGRAL and MAGIC upper limits on the high-energy emission have recently been presented. We conduct a parameter study of the set of free quantities describing the yet vaguely constrained geometry and respective effects on the non-thermal high-energy radiation from WR 147. The results are confronted with the recently obtained high-energy observations and with sensitivities of contemporaneous high-energy instruments like Fermi-LAT. For binaries with sufficient long periods, like WR 147, gamma-ray attenuation is unlikely to cause any distinctive features in the high-energy spectrum. This leaves the anisotropic inverse Compton scattering as the only process that reacts sensitively on the line-of-sight angle with respect to the orbital plane, and therefore allows the deduction of system parameters even from observations not covering a substantial part of the orbit. Provided that particle acceleration acts sufficiently effectively to allow the production of GeV photons through inverse Compton scattering, our analysis indicates a preference for WR 147 to possess a large inclination angle. Otherwise, for low inclination angles, electron acceleration is constrained to be less efficient as anticipated here.Comment: 33 pages, 9 figures; accepted by Ap

Holographic model for heavy vector meson masses

The experimentally observed spectra of heavy vector meson radial excitations show a dependence on two different energy parameters. One is associated with the quark mass and the other with the binding energy levels of the quark anti-quark pair. The first is present in the large mass of the first state while the other corresponds to the small mass splittings between radial excitations. In this article we show how to reproduce such a behavior with reasonable precision using a holographic model. In the dual picture, the large energy scale shows up from a bulk mass and the small scale comes from the position of anti-de Sitter (AdS) space where field correlators are calculated. The model determines the masses of four observed S-wave states of charmonium and six S-wave states of bottomonium with , 6.1 % rms error. In consistency with the physical picture, the large energy parameter is flavor dependent, while the small parameter, associated with quark anti-quark interaction is the same for charmonium and bottomonium states.Comment: In V5 we just added some clarifying explanations about the model. 5 tables, no figure. Version published in Europhysics Letter

Holographic Picture of Heavy Vector Meson Melting

The fraction of heavy vector mesons produced in a heavy ion collision, as compared to a proton proton collision, serves as an important indication of the formation of a thermal medium, the quark gluon plasma. This sort of analysis strongly depends on understanding the thermal effects of a medium like the plasma on the states of heavy mesons. In particular, it is crucial to know the temperature ranges where they undergo a thermal dissociation, or melting. AdS/QCD models are know to provide an important tool for the calculation of hadronic masses, but in general are not consistent with the observation that decay constants of heavy vector mesons decrease with excitation level. It has recently been shown that this problem can be overcome using a soft wall background and introducing an extra energy parameter, through the calculation of correlation functions at a finite position of anti-de Sitter space. This approach leads to the evaluation of masses and decay constants of S wave quarkonium states with just one flavor dependent and one flavor independent parameters. Here we extend this more realistic model to finite temperatures and analyse the thermal behavior of the states $1S, 2S$ and $3S$ of bottomonium and charmonium. The corresponding spectral function exhibits a consistent picture for the melting of the states where, for each flavor, the higher excitations melt at lower temperatures. We estimate for these six states, the energy ranges in which the heavy vector mesons undergo a transition from a well defined peak in the spectral function to complete melting in the thermal medium. A very clear distinction between the heavy flavors emerges, with bottomonium state $\Upsilon (1S)$ surviving deconfinemet transition at temperatures much larger than the critical deconfinement temperature of the medium.Comment: 20 pages, 7 figure

Ergodic Transport Theory, periodic maximizing probabilities and the twist condition

The present paper is a follow up of another one by A. O. Lopes, E. Oliveira and P. Thieullen which analyze ergodic transport problems. Our main focus will a more precise analysis of case where the maximizing probability is unique and is also a periodic orbit. Consider the shift T acting on the Bernoulli space \Sigma={1, 2, 3,.., d}^\mathbb{N} $and$A:\Sigma \to \mathbb{R} a Holder potential. Denote m(A)=max_{\nu is an invariant probability for T} \int A(x) \; d\nu(x) and, \mu_{\infty,A}, any probability which attains the maximum value. We assume this probability is unique (a generic property). We denote \T the bilateral shift. For a given potential Holder A:\Sigma \to \mathbb{R}, we say that a Holder continuous function W: \hat{\Sigma} \to \mathbb{R} is a involution kernel for A, if there is a Holder function A^*:\Sigma \to \mathbb{R}, such that, A^*(w)= A\circ \T^{-1}(w,x)+ W \circ \T^{-1}(w,x) - W(w,x). We say that A^* is a dual potential of A. It is true that m(A)=m(A^*). We denote by V the calibrated subaction for A, and, V^* the one for A^*. We denote by I^* the deviation function for the family of Gibbs states for \beta A, when \beta \to \infty. For each x we get one (more than one) w_x such attains the supremum above. That is, solutions of V(x) = W(w_x,x) - V^* (w_x)- I^*(w_x). A pair of the form (x,w_x) is called an optimal pair. If \T is the shift acting on (x,w) \in {1, 2, 3,.., d}^\mathbb{Z}, then, the image by \T^{-1} of an optimal pair is also an optimal pair. Theorem - Generically, in the set of Holder potentials A that satisfy (i) the twist condition, (ii) uniqueness of maximizing probability which is supported in a periodic orbit, the set of possible optimal w_x, when x covers the all range of possible elements x in \in \Sigma, is finite

Closing in on the large-scale CMB power asymmetry

Measurements of the cosmic microwave background (CMB) temperature anisotropies have revealed a dipolar asymmetry in power at the largest scales, in apparent contradiction with the statistical isotropy of standard cosmological models. The significance of the effect is not very high, and is dependent on a posteriori choices. Nevertheless, a number of models have been proposed that produce a scale-dependent asymmetry. We confront several such models for a physical, position-space modulation with CMB temperature observations. We find that, while some models that maintain the standard isotropic power spectrum are allowed, others, such as those with modulated tensor or uncorrelated isocurvature modes, can be ruled out on the basis of the overproduction of isotropic power. This remains the case even when an extra isocurvature mode fully anti-correlated with the adiabatic perturbations is added to suppress power on large scales.Comment: 6 pages, 3 figures. Comments welcom