Inferring Depth Maps from 2-Dimensional Laser Ranging Data in a Simulated Environment

Depth estimation plays a key role in mobile robotics for applications including scene understanding, navigation and mapping. Recently, deep learning methods have proven effective in estimating depth maps from a combination of different sources such as 3D LiDAR or RGB images. However, they face two challenges; the lack of dense ground truth data and the depth input sparsity, which ranges from 4-10% pixel density on an input image. This thesis explores the feasibility of inferring a full depth map from extremely sparse 2D LiDAR measurements via neural network. To address the lack of ground truth data, a simulation tool is created for data gathering. The results show that from our sparse input of 0.024% pixel density on input images, the tested network infers shapes but struggles with blurry boundaries on objects

Kerr black holes with self-interacting scalar hair: Hairier but not heavier

The maximal Arnowitt-Deser-Misner (ADM) mass for (mini) boson stars (BSs)-gravitating solitons of Einstein's gravity minimally coupled to a free, complex, mass mu, Klein-Gordon field-is M-ADM(max) similar to M-Pl(2)/mu. Adding quartic self-interactions to the scalar field theory, described by the Lagrangian L-1 = lambda vertical bar Psi vertical bar(4), the maximal ADM mass becomes M-ADM(max) similar to root lambda M-Pl(3)/mu(2). Thus, for mini-BSs, astrophysically interesting masses require ultralight scalar fields, whereas self-interacting BSs can reach such values for bosonic particles with Standard Model range masses. We investigate how these same self-interactions affect Kerr black holes with scalar hair (KBHsSH) [C. A. R. Herdeiro and E. Radu, Kerr Black Holes with Scalar Hair, Phys. Rev. Lett. 112, 221101 (2014).], which can be regarded as (spinning) BSs in stationary equilibrium with a central horizon. Remarkably, whereas the ADM mass scales in the same way as for BSs, the horizon mass M-H does not increases with the coupling., and, for fixed mu, it is maximized at the "Hod point," corresponding to the extremal Kerr black hole obtained in the vanishing hair limit. This mass is always M-H(max) similar to M-Pl(2)/mu. Thus, introducing these self-interactions, the black hole spacetimes may become considerably "hairier" but the trapped regions cannot become "heavier." We present evidence that this observation also holds in a model with L-1 = beta vertical bar Psi vertical bar(6) - lambda vertical bar Psi vertical bar(4); if it extends to general scalar field models, KBHsSH with astrophysically interesting horizon masses require ultralight scalar fields. Their existence, therefore, would be a smoking gun for such (beyond the Standard Model) particles

Shadows of Kerr Black Holes with Scalar Hair

Using backwards ray tracing, we study the shadows of Kerr black holes with scalar hair (KBHSH). KBHSH interpolate continuously between Kerr BHs and boson stars (BSs), so we start by investigating the lensing of light due to BSs. Moving from the weak to the strong gravity region, BSs-which by themselves have no shadows-are classified, according to the lensing produced, as (i) noncompact, which yield not multiple images, (ii) compact, which produce an increasing number of Einstein rings and multiple images of the whole celestial sphere, and (iii) ultracompact, which possess light rings, yielding an infinite number of images with (we conjecture) a self-similar structure. The shadows of KBHSH, for Kerr-like horizons and noncompact BS-like hair, are analogous to, but distinguishable from, those of comparable Kerr BHs. But for non-Kerr-like horizons and ultracompact BS-like hair, the shadows of KBHSH are drastically different: novel shapes arise, sizes are considerably smaller, and multiple shadows of a single BH become possible. Thus, KBHSH provide quantitatively and qualitatively new templates for ongoing (and future) very large baseline interferometry observations of BH shadows, such as those of the Event Horizon Telescope

Kerr–Newman black holes with scalar hair

We construct electrically charged Kerr black holes (BHs) with scalar hair. Firstly, we take an uncharged scalar field, interacting with the electromagnetic field only indirectly, via the background metric. The corresponding family of solutions, dubbed Kerr–Newman BHs with ungauged scalar hair, reduces to (a sub-family of) Kerr–Newman BHs in the limit of vanishing scalar hair and to uncharged rotating boson stars in the limit of vanishing horizon. It adds one extra parameter to the uncharged solutions: the total electric charge. This leading electromagnetic multipole moment is unaffected by the scalar hair and can be computed by using Gauss's law on any closed 2-surface surrounding (a spatial section of) the event horizon. By contrast, the first sub-leading electromagnetic multipole – the magnetic dipole moment –, gets suppressed by the scalar hair, such that the gyromagnetic ratio is always smaller than the Kerr–Newman value (g=2g=2). Secondly, we consider a gauged scalar field and obtain a family of Kerr–Newman BHs with gauged scalar hair. The electrically charged scalar field now stores a part of the total electric charge, which can only be computed by applying Gauss' law at spatial infinity and introduces a new solitonic limit – electrically charged rotating boson stars. In both cases, we analyze some physical properties of the solutions

Chaotic lensing around boson stars and Kerr black holes with scalar hair

In a recent paper [P. V. P. Cunha, C. A. R. Herdeiro, E. Radu, and H. F. Runarsson, Phys. Rev. Lett. 115, 211102 (2015).], it was shown that the lensing of light around rotating boson stars and Kerr black holes with scalar hair can exhibit chaotic patterns. Since no separation of variables is known (or expected) for geodesic motion on these backgrounds, we examine the 2D effective potentials for photon trajectories, to obtain a deeper understanding of this phenomenon. We find that the emergence of stable light rings on the background spacetimes allows the formation of " pockets" in one of the effective potentials, for open sets of impact parameters, leading to an effective trapping of some trajectories, dubbed " quasibound orbits." We conclude that pocket formation induces chaotic scattering, although not all chaotic orbits are associated to pockets. These and other features are illustrated in a gallery of examples, obtained with a new ray- tracing code, PYHOLE, which includes tools for a simple, simultaneous visualization of the effective potential, together with the spacetime trajectory, for any given point in a lensing image. An analysis of photon orbits allows us to further establish a positive correlation between photon orbits in chaotic regions and those with more than one turning point in the radial direction; we recall that the latter is not possible around Kerr black holes. Moreover, we observe that the existence of several light rings around a horizon (several fundamental orbits, including a stable one), is a central ingredient for the existence of multiple shadows of a single hairy black hole. We also exhibit the lensing and shadows by Kerr black holes with scalar hair, observed away from the equatorial plane, obtained with PYHOLE

Uncovering the mechanism leading to the synthesis of symmetric and asymmetric Tröger's bases

Tröger´s bases have been attracting great interest due to their potential applications in nanoelectronics, supramolecular chemistry, molecular recognition, biological activity and auxiliaries for asymmetric synthesis. However, a detailed step by step proposal for the mechanism leading to the production of these compounds is still uncovered. A set of five model syntheses of symmetric and asymmetric Tröger´s base derivatives starting from substituted anilines and formaldehyde was done and envisaged as representative for understanding the underlying mechanism. All reasonable pathways were thoroughly scanned by means of DFT calculations. The highest energy TS was associated with the entrance of the first formaldehyde which produces the first out of three key carbocations. The last step, the closure of the methylene-bridged diazocyne heterocycle was also found of kinetic relevance and as a source of stable intermediates or byproducts. The whole mechanistic picture would provide keys for the rational planning of the synthesis of these compounds.Fil: Lanza, Priscila Ailín. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Biodiversidad y Biotecnologia. Grupo de Investigacion En Quimica Analitica y Modelado Molecular.; ArgentinaFil: Dusso, Diego. Departamento de Química; ArgentinaFil: Ramirez, Cristina Lujan. Universidad Nacional de Mar del Plata; ArgentinaFil: Parise, Alejandro Ruben. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Biodiversidad y Biotecnologia. Grupo de Investigacion En Quimica Analitica y Modelado Molecular.; Argentina. Universidad Nacional de Mar del Plata; ArgentinaFil: Chesta, Carlos Alberto. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Moyano, Elizabeth Laura. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Vera, Domingo Mariano Adolfo. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Biodiversidad y Biotecnologia. Grupo de Investigacion En Quimica Analitica y Modelado Molecular.; Argentin

Resolution and Determination of the Absolute Configuration of a Twisted Bis-Lactam Analogue of Troger's Base: A Comparative Spectroscopic and Computational Study

The first reported twisted bis-lactam, a racemic Tröger's base (TB) analogue (2), was resolved into its enantiomers on a chiral stationary phase HPLC column. The absolute configuration of (+)-2 was determined to be (R,R)-2 by comparing experimental and calculated vibrational circular dichroism (VCD) and electronic circular dichroism (ECD) spectra. The absolute configuration of (-)-2 was determined by comparing experimental and calculated electronic circular dichroism (ECD) spectra. The corresponding theoretical spectra were calculated using the lowest energy conformation of (R,R)-2 and (S,S)-2 at the B3LYP/6-31G(d,p) level of theory. The absolute configuration of (+)-2 was also determined to (R,R)-2 by anomalous X-ray diffraction (AXRD) in a chiral space group P212121 using Cu-irradiation resulting in a very low Flack parameter of -0.06(3), despite the heaviest element being an oxygen atom, thus unambiguously confirming the results from the spectroscopic studies. We conclude that, for the Tröger's base (TB) analogue (2), we may rank the reliability of the individual methods for AC determination as AXRD ≫ VCD > ECD, while the synergy of all three methods provides very strong confidence in the assigned ACs of (+)-(R,R)-2 and (-)-(S,S)-2

Relatório de estágio em farmácia comunitária

Relatório de estágio realizado no âmbito do Mestrado Integrado em Ciências Farmacêuticas, apresentado à Faculdade de Farmácia da Universidade de Coimbr