Anti-de Sitter wormhole kink

The metric describing a given finite sector of a four-dimensional asymptotically anti-de Sitter wormhole can be transformed into the metric of the time constant sections of a Tangherlini black hole in a five-dimensional anti-de Sitter spacetime when one allows light cones to tip over on the hypersurfaces according to the conservation laws of an one-kink. The resulting kinked metric can be maximally extended, giving then rise to an instantonic structure on the euclidean continuation of both the Tangherlini time and the radial coordinate. In the semiclassical regime, this kink is related to the existence of closed timelike curves.Comment: 10 pages, to appear in IJMP

A dark energy multiverse

We present cosmic solutions corresponding to universes filled with dark and phantom energy, all having a negative cosmological constant. All such solutions contain infinite singularities, successively and equally distributed along time, which can be either big bang/crunchs or big rips singularities. Classicaly these solutions can be regarded as associated with multiverse scenarios, being those corresponding to phantom energy that may describe the current accelerating universe

Simulation Platform for Coordinated Charging of Electric Vehicles

EMERALD is a project funded by the European Commission under the FP7 program focusing on energy use optimization on the integration of the FEVs into the transport and energy infrastructure. Between the objectives of EMERALD, enhanced power demand prediction and power flow support management system uses the power flow demand simulation platform considered in this paper. The power flow demand simulation platform is a software tool that defines the estimation of FEVs power demand according to different conditions as, arrival and departure curves, the estimation of power production based on renewable energy sources and the electricity cost. The tool coordinates scheduling for charging of FEVs in order to minimize the recharging cost, considering the energy balance between the generation and demand powerEuropean commission's FP

Image = Structure + Few Colors

Topology plays an important role in computer vision by capturing the structure of the objects. Nevertheless, its potential applications have not been sufficiently developed yet. In this paper, we combine the topological properties of an image with hierarchical approaches to build a topology preserving irregular image pyramid (TIIP). The TIIP algorithm uses combinatorial maps as data structure which implicitly capture the structure of the image in terms of the critical points. Thus, we can achieve a compact representation of an image, preserving the structure and topology of its critical points (maxima, the minima and the saddles). The parallel algorithmic complexity of building the pyramid is O(log d) where d is the diameter of the largest object.We achieve promising results for image reconstruction using only a few color values and the structure of the image, although preserving fine details including the texture of the image

The merger history of massive spheroids since z~1 is size independent

Using a compilation of 379 massive (stellar mass M > 10^{11} M_Sun) spheroid-like galaxies from the near-infrared Palomar/DEEP-2 survey, we have probed, up to z~1, whether the presence of companions depends on the size of the host galaxies. We have explored the presence of companions with mass ratios down to 1:10 and 1:100, with respect to the central massive galaxy, and within a projected distance of 30, 50 and 100 kpc of these objects. We find evidence for these companions being equally distributed around both compact and extended massive spheroids. This finding suggests that, at least since z~1, the merger activity in these objects is rather homogeneous across the whole population and its merger history is not affected for the size of the host galaxy. Our result could indicate that both compact and extended massive spheroid-like galaxies are growing in size at the same rate.Comment: 9 pages, 6 figures, accepted for publication in MNRA

Wormholes and Ringholes in a Dark-Energy Universe

The effects that the present accelerating expansion of the universe has on the size and shape of Lorentzian wormholes and ringholes are considered. It is shown that, quite similarly to how it occurs for inflating wormholes, relative to the initial embedding-space coordinate system, whereas the shape of the considered holes is always preserved with time, their size is driven by the expansion to increase by a factor which is proportional to the scale factor of the universe. In the case that dark energy is phantom energy, which is not excluded by present constraints on the dark-energy equation of state, that size increase with time becomes quite more remarkable, and a rather speculative scenario is here presented where the big rip can be circumvented by future advanced civilizations by utilizing sufficiently grown up wormholes and ringholes as time machines that shortcut the big-rip singularity.Comment: 11 pages, RevTex, to appear in Phys. Rev.

Ciudad inteligente y sostenible: Singapore, caso de éxito

The following paper focuses on the qualitative description of the nation city of Singapore and its quantitative evaluation, which are part of an exploratory research for the ORCA and SciBas research group of the Francisco José de Caldas District University. Therefore, during the first semester of 2018, a conceptual review was made on the subject, proposing an action methodology whose snuyources are selected with the category of smart city in the context of sustainability. The search for information, both national and international, was focused on the databases: IEEE Xplore, ScienceDirect, Springer Link, among others; and in the search for the evaluation model.El siguiente trabajo se centra en la descripción cualitativa de la ciudad nación de Singapur y su evaluación cuantitativa, que hacen parte de una investigación exploratoria para el grupo de investigación ORCA y SciBas de la Universidad Distrital Francisco José de Caldas. Por lo tanto, durante el primer semestre de 2018, se realizó una revisión conceptual sobre el tema, proponiendo una metodología de acción cuyas fuentes son seleccionadas con la categoría de ciudad inteligente en el contexto de la sostenibilidad. La búsqueda de información, tanto nacional como internacional, se centró en las bases de datos: IEEE Xplore, ScienceDirect, Springer Link, entre otras; y en la búsqueda del modelo de evaluación

Soil and water pollution in a banana production region in tropical Mexico

The effects of abundant Mancozeb (Mn, Zn— bisdithiocarbamate) applications (2.5 kg ha-1week-1 for 10 years) on soil and surface-, subsurface- and groundwater pollution were monitored in a banana production region of tropical Mexico. In soils, severe manganese accumulation was observed, wheras the main metabolite ethylenethiourea was near the detection limit. Surface and subsurface water was highly polluted with ethylenethiourea, the main metabolite of Mancozeb (22.5 and 4.3 lg L-1, respectively), but not with manganese. In deep ground water, no ethylenethiourea was detected. The level of pollution in the region presents a worrisome risk for aquatic life and for human health