Town planning and public housing

During the last seven years, Spain has experience importans legislativies changes in land and housing materia. The land law of 1990, conceive the urbanistic proficience as colectivity result and the cession of part of this proficience to the land owner. This law changes the point of view about the land ownership. The use of this legislation with the objetive to maximice the colectivity utility to a minimun ejecutation cost and the transfer of the proficience from some town zones to others, building systems of distribution of charges and benefits. The city of Cadiz is a particular case where is used and checked. With the housing legislation has been posible the creation of public housing companies, perfect complement to the public intervencion in thats materials. A special case is the San Fernando public housing company (Cadiz) with the objetive of intervention in the low rent housing market without cost for the Local Administration. Keywords: Town Planning, Public Intervention, Housing.

Constraining the halo mass function with observations

The abundances of dark matter halos in the universe are described by the halo mass function (HMF). It enters most cosmological analyses and parametrizes how the linear growth of primordial perturbations is connected to these abundances. Interestingly, this connection can be made approximately cosmology independent. This made it possible to map in detail its near-universal behavior through large-scale simulations. However, such simulations may suffer from systematic effects, especially if baryonic physics is included. In this paper we ask how well observations can constrain directly the HMF. The observables we consider are galaxy cluster number counts, galaxy cluster power spectrum and lensing of type Ia supernovae. Our results show that DES is capable of putting the first meaningful constraints on the HMF, while both Euclid and J-PAS can give stronger constraints, comparable to the ones from state-of-the-art simulations. We also find that an independent measurement of cluster masses is even more important for measuring the HMF than for constraining the cosmological parameters, and can vastly improve the determination of the halo mass function. Measuring the HMF could thus be used to cross-check simulations and their implementation of baryon physics. It could even, if deviations cannot be accounted for, hint at new physics.Comment: v2: small improvements to the text; matches accepted version. 13 pages, 8 figure

Turning noise into signal: learning from the scatter in the Hubble diagram

The supernova (SN) Hubble diagram residual contains valuable information on both the present matter power spectrum and its growth history. In this paper we show that this information can be retrieved with precision by combining both peculiar velocity and weak-lensing analysis on the data. To wit, peculiar velocity induces correlations on the nearby SN while lensing induces a non-Gaussian dispersion in faraway objects. We show that both effects have almost orthogonal degeneracies and discuss how they can be extracted simultaneously from the data. We analyze the JLA supernova catalog in a 14-dimensional parameter space, assuming a flexible growth-rate index $\gamma$. We arrive at the following marginalized constraints: $\sigma_8 = 0.65^{+0.23}_{-0.37}$ and $\gamma = 1.38^{+1.7}_{-0.65}$. Assuming instead GR as the correct gravitation theory (and thus $\gamma \equiv 0.55$), the constraints in $\sigma_8$ tighten further: $\sigma_8 = 0.40^{+0.21}_{-0.23}$. We show that these constraints complement well the ones obtained from other datasets and that they could improve substantially with more SNe.Comment: v2: Real data results corrected; forecast for future data added; discussion extended. v3: Improved discussion; matches published version. 8 figs 15 page

Dirac points merging and wandering in a model Chern insulator

We present a model for a Chern insulator on the square lattice with complex first and second neighbor hoppings and a sublattice potential which displays an unexpectedly rich physics. Similarly to the celebrated Haldane model, the proposed Chern insulator has two topologically non-trivial phases with Chern numbers $\pm1$. As a distinctive feature of the present model, phase transitions are associated to Dirac points that can move, merge and split in momentum space, at odds with Haldane's Chern insulator where Dirac points are bound to the corners of the hexagonal Brillouin zone. Additionally, the obtained phase diagram reveals a peculiar phase transition line between two distinct topological phases, in contrast to the Haldane model where such transition is reduced to a point with zero sublattice potential. The model is amenable to be simulated in optical lattices, facilitating the study of phase transitions between two distinct topological phases and the experimental analysis of Dirac points merging and wandering

Optimization of the ionization time of an atom with tailored laser pulses: a theoretical study

How fast can a laser pulse ionize an atom? We address this question by considering pulses that carry a fixed time-integrated energy per-area, and finding those that achieve the double requirement of maximizing the ionization that they induce, while having the shortest duration. We formulate this double-objective quantum optimal control problem by making use of the Pareto approach to multi-objetive optimization, and the differential evolution genetic algorithm. The goal is to find out how much a precise time-profiling of ultra-fast, large-bandwidth pulses may speed up the ionization process with respect to simple-shape pulses. We work on a simple one-dimensional model of hydrogen-like atoms (the P\"oschl-Teller potential), that allows to tune the number of bound states that play a role in the ionization dynamics. We show how the detailed shape of the pulse accelerates the ionization process, and how the presence or absence of bound states influences the velocity of the process

Constraining the growth of perturbations with lensing of supernovae

A recently proposed technique allows one to constrain both the background and perturbation cosmological parameters through the distribution function of supernova Ia apparent magnitudes. Here we extend this technique to alternative cosmological scenarios, in which the growth of structure does not follow the $\Lambda$CDM prescription. We apply the method first to the supernova data provided by the JLA catalog combined with all the current independent redshift distortion data and with low-redshift cluster data from Chandra and show that although the supernovae alone are not very constraining, they help in reducing the confidence regions. Then we apply our method to future data from LSST and from a survey that approximates the Euclid satellite mission. In this case we show that the combined data are nicely complementary and can constrain the normalization $\sigma_8$ and the growth rate index $\gamma$ to within $0.6\%$ and $7\%$, respectively. In particular, the LSST supernova catalog is forecast to give the constraint $\gamma (\sigma_8/0.83)^{6.7} = 0.55 \pm 0.1$. We also report on constraints relative to a step-wise parametrization of the growth rate of structures. These results show that supernova lensing serves as a good cross-check on the measurement of perturbation parameters from more standard techniques.Comment: 9 pages, 7 figures, matches version accepted for publication in MNRAS. Added appendix with fits of lensing moments as function of (z, \sigma_8, \gamma). The updated turboGL 3.0 code can be downloaded at http://www.turbogl.or

Retail trade as a tool to create a border identity

Desde sempre as localidades próximas das fronteiras estabeleceram relações entre as suas populações - familiares, de trabalho e, talvez as mais antigas, comerciais. Desde sempre o factor barreira, induzido pela fronteira, não representou obstáculo às relações entre povos. Dependendo da porosidade da fronteira, as relações podem tornar-se mais ou menos intensas, mais ou menos tranquilas, mas nunca nulas. O contrabando e o aproveitamento das vantagens comparativas entre dois países proporcionaram sempre contactos e uma alteridade que potencia a formação de uma identidade na população, que não deixando de ser nacional, é, simultaneamente, transfronteiriça. No caso da fronteira interna da Península Ibérica, sempre se puderam verificar relações comerciais que, essencialmente após a adesão dos dois países à U. Europeia, e mais concretamente a partir de Schengen, se intensificaram, devido à diluição do efeito de barreira. No caso do polígono formado por Portalegre/Elvas/Badajoz/Valência de Alcântara verifica-se que o factor de maior aproximação entre as populações é o comércio a retalho e que este, directa ou indirectamente, influencia o crescimento e a expansão urbanos