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El Servicio Geológico Colombiano (SGC) y la Universidad Pedagógica y Tecnológica de Colombia (UPTC) presentan a la comunidad geocientífica la publicación Neotectónica y paleosismología de la Falla de Algeciras, Huila, Colombia. Este libro refleja las actividades de las dos instituciones, bajo el convenio 022 de 2019, con recursos del Sistema General de Regalías, asignados al proyecto Modelo Tectónico de la Dirección de Geociencias del SGC. Investigadores de los grupos de investigación en Geodinámica (antes Tectónica) de la Dirección de Geociencias Básicas y de Investigaciones Geodésicas Espaciales de la Dirección de Geoamenazas del SGC, junto con investigadores de la Escuela de Ingeniería Geológica de la UPTC, Sogamoso, expertos internacionales de Holanda y Venezuela y el apoyo de la Universidad Distrital Francisco José de Caldas unieron sus esfuerzos para emplear las técnicas más relevantes en las investigaciones neotectónicas y paleosismológicas, de vital importancia para ser aplicadas en el país. Sin lugar a dudas los resultados permiten avanzar en el conocimiento del Sistema de Fallas de Algeciras, probablemente el sistema de fallas más representativo de Colombia continental en términos de su potencial sismogénico, y proporcionan información valiosa para el avance del conocimiento de la amenaza sísmica del país.

The deformation registered in rocks in the field can be characterized based on the structures preserved in outcrops, which can related be to wide discontinuity zones named faults and shear zones. The geological-structural mapping and the geochronology of these tectonic structures are a topic of great interest not only for tectonic modeling but also for reconstruction of the geological evolution of the national territory. The methodology suggest for the analysis of faults and shear zones is based on eight steps, including: 1) definition of the geological context in which the structure was developed; 2) photointerpretation, image geoprocessing, and geological-structural mapping of the structural and lithological characteristics of the faults and shear zones; 3) petrographic analysis of field-oriented samples; 4) quantification of strain orientation and geometry through 3D finite strain analyses and quantification of non-coaxiliaty of deformation through vorticity analyses; 5) SEM-TEM-EBSD microanalysis; 6) quantification of the P-T conditions of deformation through phase-equilibria modeling or conventional geothermobarometry; 7) dating of syn-kinematic minerals phases and mylonitic rocks through Ar-Ar analyses, in order to determine the reactivation and deformation ages of the structure, respectively, as well as the implementation of the U-Pb technique in syn-kinematic calcite crystals developed in the fault planes; and 8) dating of geological elements adjacent to the structure, such as syn-kinematic intrusive bodies associated with the deformation event using zircon U-Pb dating, rocks hydrothermally altered through Ar-Ar method, and zircon and apatite fission-tracks dating of the blocks adjacent to the faults for determining exhumation ages.

In this paper an implementation of a fuzzy adaptive control law to manipulate device of Human-Robot interaction is presented. Mamdani type fuzzy systems are employed to approximate the dynamics of interaction system. An adaptation law is added to controller to compensate for parametric variations and/or uncertainties of the interaction human-robot. The theoretical results proposed are illustrated on a PHANToM Premium 1.0 haptic device.

En un escenario en el que hay un número reducido de usuarios de telefonía IP, hay varias alternativas para prestar el servicio de forma que no se incurra en la subutilización de los recursos. Una de estas alternativas es utilizar como servidor, un ordenador de bajo costo como la raspberry pi, el cual tiene la ventaja de presentar un bajo consumo de potencia. Este trabajo muestra el procedimiento, y los resultados, de una evaluación de rendimiento realizada a un servidor de telefonía IP, el cual tiene la funcionalidad de un PBX IP, usando como plataforma una tarjeta raspberry pi modelo B. Dicha evaluación tiene como finalidad determinarlas características de desempeño básicas de la alternativa teniendo en cuenta aspectos como: el consumo de potencia y la calidad del servicio. Como resultado se tiene que la alternativa presentada en este artículo, es una buena opción en escenarios donde sea suficiente un servidor con capacidad para 7 llamadas concurrentes.

Enantiomerically pure 2-p-tolylsulfinylmaleates 1, 2 and 3 have been readily prepared by Knoevenagel reaction between (S)-menthyl p-toluenesulfinate and glyoxylic acid. Their asymmetric Diels-Alder reactions with cyclopentadiene have been studied under a wide range of uncatalyzed and catalyzed conditions and the stereochemical results have been explained by assuming a steric control approach, in term of S-cis or S-trans favoured conformations. Uncatalyzed Diels-Alder reactions of 1 and some Lewis acid catalyzed Diels-Alder reactions of 2 show high facial and endo selectivities. The facial selectivity of dienophile 2 highly depends on the Lewis acid, whereas reactivity of 1 and 3 is very sensitive to the solvent. These sulfinylmaleates 1, 2 and 3 act as synthetic equivalents of chiral acetylenedicarboxylates in Diels-Alder reactions after basic elimination of the sulfinylic moiety in the resulting adducts.

The title compounds 6 and 7 have proved to be adequate rigid models to evaluate the ability of the sulfinyl group to control the diastereoselectivity of the [4 + 2] cycloadditions of cyclopentadiene on the ene-dione moiety. The results of thermal and Lewis acid-catalyzed reactions allowed us to establish that both reactivity and endo/exo selectivity were modulated by the presence of the sulfinyl group, the endo-anti-endo or the exo-anti-endo bisadducts being obtained as major products depending on experimental conditions. The role of the association between the SOTol group and several Lewis acids (BF(3).OEt(2), Eu(fod)(3), ZnBr(2)), which shifted the conformational equilibrium around the C-S bond, was used to explain the stereochemical course of the cycloadditions mainly controlled by steric factors. The synthesis of the exo-anti-endo bisadduct 5 was described for the first time.

The conformational analysis of the diastereomeric 2-methylsulphinyl-1-phenylethanol and its O-methyl and O-acetyl derivatives has been performed by 1H NMR spectroscopy. The study of the influence of dilution and solvent polarity changes on the coupling constants has permitted the configurational assignment of each diastereoisomer. The role played by hydrogen bonding in the hydroxysulphoxides has also been studied by IR spectroscopy.

We deposited discontinuous gold films of various thicknesses onto muscovite mica by high vacuum evaporation. The deposition onto the substrate took place at room temperature, which is insufficient for epitaxial orientation of the metal. X-ray diffraction showed the absence of a defined azimuthal orientation of the polycrystalline gold film. Using the Au/mica system described as a substrate, a deposit of NH4I from its saturated aqueous solution showed epitaxial orientation. When silver was evaporated onto the Au/mica system as a substrate (which was heated to 200 °C during the deposition), it showed epitaxial orientation as observed in a Laue photograph. This orientation was similar to the epitaxy of silver on a mica substrate. The Au/mica system keeps its epitaxial power for periods from 1 to 2 months. Substrates of mica without gold lose their epitaxial power in a few hours. The results obtained suggest that the discontinuities of the gold film make it possible for the same distribution of charges to exist on the metal surface as on the surface of the recently cleaved mica.