On the construction of a finite Siegel space

In this note we construct a finite analogue of classical Siegel's Space. Our approach is to look at it as a non commutative Poincare's half plane. The finite Siegel Space is described as the space of Lagrangians of a $2n$ dimensional space over a quadratic extension $E$ of a finite base field $F$. The orbits of the action of the symplectic group $Sp(n,F)$ on Lagrangians are described as homogeneous spaces. Also, Siegel's Space is described as the set of anti-involutions of the symplectic group.2

Symmetries of distributional domain wall geometries

Generalizing the Lie derivative of smooth tensor fields to distribution-valued tensors, we examine the Killing symmetries and the collineations of the curvature tensors of some distributional domain wall geometries. The chosen geometries are rigorously the distributional thin wall limit of self gravitating scalar field configurations representing thick domain walls and the permanence and/or the rising of symmetries in the limit process is studied. We show that, for all the thin wall spacetimes considered, the symmetries of the distributional curvature tensors turns out to be the Killing symmetries of the pullback of the metric tensor to the surface where the singular part of these tensors is supported. Remarkably enough, for the non-reflection symmetric domain wall studied, these Killing symmetries are not necessarily symmetries of the ambient spacetime on both sides of the wall

Algorithms for constrained optimization

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Ensambles de arqueas y bacterias en la Zona de Mínimo Oxígeno del ecosistema de surgencia de Chile central determinados mediante biomarcadores orgánicos

Indexación: Web of Science; Scielo.Organic biomarkers were used to investigate the influence of seasonal changes in oxygenation and water chemistry on the distribution of archaea and bacteria in the water column and surface sediments of the continental shelf off central Chile (ca. 36°S), an area influenced by seasonal upwelling and the development of an oxygen minimum zone. We were interested in establishing if occurrence of archaea and bacteria responds to oxygenation and water chemistry for which we analyzed archaeal isoprenoid (i) and bacterial branched (br) glycerol dialkyl glycerol tetraethers (GDGTs). Our results combined with molecular data from a year round observational program at the same sampling site and depths indicatives the occurrence and dominance of the marine pelagic group Thaumarchaeota. Changes in the distribution of iGDGTs might be explained by (i) the presence of archaeal populations in sub-oxic waters, phylogenetically different from those in surface water, (ii) changes in the relative contribution of Euryarchaeota with depth, and (iii) a relationship between Thaumarchaeota and environmental factors other than temperature. Branched GDGTs were more abundant in the upper, oxic layer during the non-upwelling season, may be a result of higher river runoff, whereas their diversity was higher within sub-oxic waters. Our results indicate a vertical segregation of iGDGTs and brGDGTs, with predominance of archaeal biomarkers during the low productivity season.Se utilizaron biomarcadores orgánicos en para investigar la influencia de cambios estacionales en los niveles de oxigenación y la química del agua sobre la distribución de arqueas y bacterias en la columna de agua y los sedimentos superficiales de la plataforma continental frente a Chile central, un área influenciada por surgencia estacional asociada al desarrollo de una zona de mínimo oxígeno. Nuestro interés es establecer si la ocurrencia de arquea y bacteria responde a la oxigenación y química del agua para lo cual analizamos gliceroles dialquil gliceroles tetra-éteres (GDGTs) isoprenoides arqueanos (i) y ramificados bacterianos (r). Nuestros resultados, combinados con datos moleculares de observaciones durante un año en el mismo lugar y profundidades del sitio de estudio indican la presencia y dominancia del grupo arqueano marino- pelágico Thaumarchaeota. Los cambios observados en la distribución de iGDGTs podrían explicarse por (i) la presencia de poblaciones de arqueas marinas en la capa de agua sub-óxica, filogenéticamente diferentes a las de aguas superficiales, (ii) cambio en la contribución relativa de Euryarchaeota con profundidad, y (iii) una relación entre Thaumarchaeota y factores ambientales distintos a la temperatura. Los GDGTs ramificados fueron más abundantes en la capa óxica superior durante el periodo de no-surgencia, tal vez influenciado por la alta descarga de ríos, mientras que su diversidad fue más alta en el agua sub-óxica. Nuestros resultados indican una segregación vertical de los GDGTs isoprenoides y ramificados, con el predominio de biomarcadores arqueanos durante el periodo de baja productividad.http://ref.scielo.org/vq5y7

Software toolset to enable image classification of earthquake damage to above-ground infrastructure

A critical task after a significant earthquake is determining the extent of damage to infrastructure networks. The decision-making process to dispatch emergency, repair, and in-field reconnaissance teams depends on whether road/railways and bridges are passible. Another concern is the rapid identification and resolution of physical disruptions to large-volume gas and water pipeline systems. After large seismic events, citizens, amateur photographers, and journalists now post thousands of photographs to formal/social media platforms. In the past, these images would have had to be reviewed by trained volunteers or expert engineers to evaluate whether: road/rail ways were significantly impacted by ground fracture, heaving, slope failure, or rock slides; bridges experienced severe damage or partial-to-complete collapse; and pipeline systems were interrupted by differential ground movement or liquefaction. The manual review of large imagesets for assessing damage has shown to be inefficient and, in cases, error-prone. This paper presents an automatic and rapid approach, based on computer vision techniques, to assessing damage to above-ground infrastructure networks via images uploaded in the immediate aftermath of the earthquake. The authors developed an algorithm based on deep learning (DL) that automatically tags images. Progress to date shows the algorithm correctly assigns individual tags to 92% of roadway images exhibiting cracking (of varying directionality and severities) and 80% of railways affected by horizontal offset (lateral translation). These results show promise and future research efforts entail tagging both of the aforementioned damage types in a single image

Photo Tagging Tool for Rapid and Detailed Post-Earthquake Structural Damage Identification

A significant task in earthquake reconnaissance is to conduct rapid and accurate assessments of damage to built infrastructure. This can be accomplished, in part, by analyzing the large volumes of high-resolution image data collected after a seismic event. However, detailed image tagging remains a task for trained human volunteers, which is both time-intensive and error prone. The authors developed a software tool to simplify and standardize the process of assigning damage and structure pairs to sub-regions of images. The goal of the tool is to facilitate the tagging of thousands of images from historic and recent earthquakes to train a deep learning (DL) algorithm to automatically identify damage observed in civil infrastructure. DL is a subset of machine learning that can be used for image classification problems. This process requires thousands of expertly tagged images for robust and automatic visual recognition capabilities. In detecting specific structural damage after an earthquake, images must have explicit tags for the building material, damage and location, as well as the impacted structural members. To obtain such a descriptive set of images, there is a need for a task-specific tool that facilitated tagging of the most common post-earthquake structural damage types. The resulting software solution consists of a simple user interface that displays the most frequently used damage and structural member tags as pre-loaded radio buttons and includes the flexibility for users to customize tags when necessary. The program generates marked-up images that show location-specific damage and structural member labels, as well as output files in the PASCAL Visual Object Classes (VOC) format that are compatible with TensorFlow and most DL frameworks, such that tagged images are ready to be used for training a DL algorithm

High-performance 16-way Ku-band radial power combiner based on the TE01-circular waveguide mode

This work presents a 16-way Ku-band radial power combiner for high power and high frequency applications, using the very low loss TE01 circular waveguide mode. The accomplished design shows an excellent performance: the experimental prototype has a return loss better than 30 dB, with a balance for the amplitudes of ( 0.15 dB) and ( 2.5 ) for the phases, in a 16.7% fractional bandwidth (2 GHz centered at 12 GHz). For obtaining these outstanding specifications, required, for instance, in highfrequency amplification or on plasma systems, a rigorous step-by-step procedure is presented. First, a high-purity mode transducer has been designed, from the TE10 mode in the rectangular waveguide to the TE01 mode in the circularwaveguide, with very high attenuation (>50 dB) for the other propagating and evanescent modes in the circularwaveguide. This transducer has been manufactured and measured in a back-to-back configuration, validating the design process. Second, an E-plane 16-way radial power divider has been designed, where the power is coupled from the 16 non-reduced-height radial standardwaveguides into the TE01 circularwaveguide mode, improving the insertion loss response and removing the usual tapered transformers of previous designs limiting the power handling. Finally, both the transducer and the divider have been assembled to make the final radial combiner. The prototype has been carefully manufactured, showing very good agreement between the measurements and the full-wave simulationsThe authors would like to thank INMEPRE S.A., the diligence in the manufacturing process. This work was supported by the Spanish government under Grant (ADDMATE) No. TEC2016-76070-C3-1/2-R (AEI/FEDER/UE) and the program of Comunidad de Madrid S2013/ICE-3000 (SPADERADARCM

Localizing gravity on exotic thick 3-branes

We consider localization of gravity on thick branes with a non trivial structure. Double walls that generalize the thick Randall-Sundrum solution, and asymmetric walls that arise from a Z_2-symmetric scalar potential, are considered. We present a new asymmetric solution: a thick brane interpolating between two AdS_5 spacetimes with different cosmological constants, which can be derived from a ``fake supergravity'' superpotential, and show that it is possible to confine gravity on such branes.Comment: Final version, minor changes, references adde