2,405 research outputs found
Shape, spin and baryon fraction of clusters in the MareNostrum Universe
The MareNostrum Universe is one of the largest cosmological
SPH simulation done so far. It consists of dark and
gas particles in a box of 500 Mpc on a side. Here we study
the shapes and spins of the dark matter and gas components of the 10,000 most
massive objects extracted from the simulation as well as the gas fraction in
those objects. We find that the shapes of objects tend to be prolate both in
the dark matter and gas. There is a clear dependence of shape on halo mass, the
more massive ones being less spherical than the less massive objects. The gas
distribution is nevertheless much more spherical than the dark matter, although
the triaxiality parameters of gas and dark matter differ only by a few percent
and it increases with cluster mass. The spin parameters of gas and dark matter
can be well fitted by a lognormal distribution function. On average, the spin
of gas is 1.4 larger than the spin of dark matter. We find a similar behavior
for the spins at higher redshifts, with a slightly decrease of the spin ratios
to 1.16 at The cosmic normalized baryon fraction in the entire cluster
sample ranges from , at to at . At both
redshifts we find a slightly, but statistically significant decrease of
with cluster mass.Comment: 7 pages, 6 figures. Accepted for publication in The Astrophysical
Journa
MS-ReRO and D-ROSE methods: Assessing relational uncertainty and evaluating scenarios risks and opportunities on multi-scale infrastructure systems
[EN] There is a growing interest in model-based decision support systems contributing to strategic planning. The application of these in the case of urban infrastructure planning requires methods specifically aimed at addressing the relational uncertainties arising from the complex, multi-scale, nature of this field. This study presents UPSS, a comprehensive urban planning support system integrating the generation of planning alternatives, the evaluation of alternatives under a set of relevant scenarios selected dynamically in a cognitive way, and the proposal of policies to accompany the planning alternative. For this purpose, UPSS integrates two novel methods. These deal respectively with the ex post identification of relevant scenarios for the evaluation of the vulnerability and resilience of the alternatives, and with the assessment of relational uncertainty. According to the risks and opportunities borne by the system, the process makes it possible to select an infrastructure plan to alleviate the problem of urban vulnerability, as well as a set of relational contracts for its proper implementation across the different governmental scales of the infrastructure system. The whole process is tested via a case study, in which USPP first proposes optimal urban infrastructure plans that contribute to ameliorate the problem of urban vulnerability in Spain, then evaluates the risks and opportunities attached to the planning alternatives, and finally presents sets of policy measures to accompany the implementation of the alternative selected.The authors acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness, along with FEDER funding (Project: BIA2017-85098-R).Salas, J.; Yepes, V. (2019). MS-ReRO and D-ROSE methods: Assessing relational uncertainty and evaluating scenarios risks and opportunities on multi-scale infrastructure systems. Journal of Cleaner Production. 216:607-623. https://doi.org/10.1016/j.jclepro.2018.12.083S60762321
Urban vulnerability assessment: Advances from the strategic planning outlook
[EN] Urban strategic planning and urban vulnerability assessment have increasingly become important issues in both policy agenda and academia. However, a comprehensive review of the advances made in urban vulnerability, emphasizing their shared aspects, has yet to be performed. The aiming of this paper is to addresses the latter by conducting an evaluation on assessment methods disclosed in this decade. Once their common evolutive pathway is traced, the review follows an analytical framework, based on the above, evaluating the research requirements from both a quantitative and qualitative point of view. Our findings indicate that the robustness, cognitive and participatory research lines are those in which most advancement has been made, while those of urban dynamics and multi-scale progressed the least. Our analysis also demonstrates that methods integrating more lines of research, as well as the employment of comprehensive approaches, promotes advancing the developmental stage. We conclude that the focusing of research lines should be shifted, in order to bridge the qualitative gap identified without demanding an improbable, quantitative increase.The authors acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness, along with FEDER funding (Project: BIA2017-85098-R).Salas, J.; Yepes, V. (2018). Urban vulnerability assessment: Advances from the strategic planning outlook. Journal of Cleaner Production. 179:544-558. https://doi.org/10.1016/j.jclepro.2018.01.088S54455817
CP violation with a dynamical Higgs
We determine the complete set of independent gauge and gauge-Higgs CP-odd
effective operators for the generic case of a dynamical Higgs, up to four
derivatives in the chiral expansion. The relation with the linear basis of
dimension six CP-odd operators is clarified. Phenomenological applications
include bounds inferred from electric dipole moment limits, and from present
and future collider data on triple gauge coupling measurements and Higgs
signals.Comment: 41 pages, 3 figures; V2: citations added, typos corrected, version
published on JHE
Las terrazas del río Miño en el tramo Chantada-As Neves (límite de Galicia-Portugal)
La cartografía geomorfológica es especialmente difícil en áreas con depósitos escasos, poco significativos y de cronología incierta, con formas multiedad y multiorigen. Tal es el caso de Galicia. Este trabajo es un intento de reconstruir la historia geomorfológica de Galicia durante el Cenozoico en un área especialmente relevante por su situación geodinámica. Se ha hecho un inventario exhaustivo de los niveles de terrazas erosivas y de acumulación en un tramo específico, por sus características morfológicas del curso principal del río Miño. Se presentan aquí los sistemas de terrazas entre Chantada y As Neves y se relacionan con las tres superficies de corrosión química (etched surfaces) más relevantes en la zona: R800, R600 y R400. Se analiza también su relación con el perfil longitudinal del río. Utilizando los únicos criterios existentes (continuidad topogr á fica y altitud), se propone para el sector estudiado un modelo evolutivo esencialmente determinado por la incisión fluvial asociada a la colisión entre la Placa Euroasiática y la Ibérica durante el Paleógeno y que geomorfológicamente se inicia a partir de la formación del aplanamiento R6 0 0, equivalente en Galicia a la Superficie Fundamental Peninsular.Geomorphologic mapping is specially difficult in areas with scarce deposits of uncertain chronology and with multiage and multiorigin forms. This is the case of Galicia. This paper is an attempt to reconstruct the geomorphologic history of Galicia during the Cenozoic in an area especially relevant because of its geodynamic situation. It has been made an exhaustive inventory of the erosive and accumulation terrace levels in a specific section of the Miño, the main river course of the region. Here it is presented the terrace levels list between Chantada and As Neves, their relation to the three etched surfaces R800, R600 and R400, wich are the most relevant because of their areal extent. It is also analyzed their relationship with the longitudinal profile of the river. Using the only existing criteria, i.e., topographic continuity and altitude, it is proposed an evolutionary model substantially determined by the river incision associated with the Paleogene collision among the Euro-Asian and the Iberian Plates. This process geomorphologically begun after the generation of R600 surface which is equivalent in Galicia to the Peninsular Fundamental Surface
High resolution simulations of the reionization of an isolated Milky Way - M31 galaxy pair
We present the results of a set of numerical simulations aimed at studying
reionization at galactic scale. We use a high resolution simulation of the
formation of the Milky Way-M31 system to simulate the reionization of the local
group. The reionization calculation was performed with the post-processing
radiative transfer code ATON and the underlying cosmological simulation was
performed as part of the CLUES project. We vary the source models to bracket
the range of source properties used in the literature. We investigate the
structure and propagation of the galatic ionization fronts by a visual
examination of our reionization maps. Within the progenitors we find that
reionization is patchy, and proceeds locally inside out. The process becomes
patchier with decreasing source photon output. It is generally dominated by one
major HII region and 1-4 additional isolated smaller bubbles, which eventually
overlap. Higher emissivity results in faster and earlier local reionization. In
all models, the reionization of the Milky Way and M31 are similar in duration,
i.e. between 203 Myr and 22 Myr depending on the source model, placing their
zreion between 8.4 and 13.7. In all models except the most extreme, the MW and
M31 progenitors reionize internally, ignoring each other, despite being
relatively close to each other even during the epoch of reionization. Only in
the case of strong supernova feedback suppressing star formation in haloes less
massive than 10^9 M_sun, and using our highest emissivity, we find that the MW
is reionized by M31.Comment: Accepted for publication in ApJ. 14 pages, 4 figures, 1 tabl
Las terrazas del río Miño en el tramo Chantada-As Neves (límite de Galicia-Portugal)
Geomorphologic mapping is specially difficult in areas with scarce deposits of uncertain chronology and with multiage and multiorigin forms. This is the case of Galicia. This paper is an attempt to reconstruct the geomorphologic history of Galicia during the Cenozoic in an area especially relevant because of its geodynamic situation. It has been made an exhaustive inventory of the erosive and accumulation terrace levels in a specific section of the Miño, the main river course of the region. Here it is presented the terrace levels list between Chantada and As Neves, their relation to the three etched surfaces R800, R600 and R400, wich are the most relevant because of their areal extent. It is also analyzed their relationship with the longitudinal profile of the river. Using the only existing criteria, i.e., topographic continuity and altitude, it is proposed an evolutionary model substantially determined by the river incision associated with the Paleogene collision among the Euro-Asian and the Iberian Plates. This process geomorphologically begun after the generation of R600 surface which is equivalent in Galicia to the Peninsular Fundamental Surface
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