Enclave Minero en el Departamento de La Serena. La Mina El Tofo, 1913-1930

This article aims to analyze the beginnings of iron mining in Chile from the experience of the El Tofo mine. In this field, the early twentieth century began the exploitation of mineral linking with an incipient domestic steel industry, which in a first stage placed the Tofo under French administration, and later, of Bethlehem Chile, US-owned company who would be responsible for modernizing and transforming the El Tofo mine in a mining enclave located in the province of Coquimbo. Their tasks differed in various hues, which included the Tofo in Chile in what was termed the mining sector. This type of extraction system is profoundly differed from traditional mining system in the province. For a better understanding of the process tested, the analysis has been divided on the French stage and the American stage with their respective contributions and transformations, use of technology and investment grade made. Finally, addressing the way how this iron mine became a mining enclave, with a low level of linkage with their environment as economic and social aspects.Este artículo tiene por finalidad analizar los inicios de la minería del hierro en Chile a partir de la experiencia de la mina El Tofo. En este yacimiento, a principios del siglo veinte comenzó la explotación de minerales vinculándose con una incipiente industria siderúrgica nacional, lo que en una primera etapa colocó al Tofo bajo una administración francesa, y más tarde, de la Bethlehem Chile, de capitales estadounidenses, empresa quién sería la encargada de modernizar y transformar la mina El Tofo en un enclave minero ubicado en la provincia de Coquimbo. Sus faenas se diferenciaron por variados matices, lo que incluyó al Tofo en lo que en Chile se denominó la gran minería. Este tipo de sistema extractivo se diferenció profundamente del sistema de la minería tradicional de la provincia. Para una mejor comprensión del proceso analizado, se ha divido el análisis en la etapa francesa y la etapa estadounidense, con sus respectivos aportes y transformaciones, usos de tecnologías y grados de inversión realizados. Finalmente, abordar la manera en cómo esta mina de hierro se convirtió en un enclave minero, con un bajo nivel de vinculación con su entorno en cuanto aspectos económicos y sociales

Diversity of Easter Island Actinobacteria and their secondary metabolites

We investigated the Actinobacterial diversity of the coastal zone of Easter Island, Chile. Additionally, we evaluated the secondary metabolites being produced by the Actinobacterial symbionts of an Easter sea anemone. Finally, we compared the secondary metabolites of two Streptomyces strains with identical 16S rRNA gene marker to determine whether or not these Streptomyces have identical chemical production capacities

Diseño sísmico de taludes en arena por medio de métodos basados en desempeño

Tesis (Ingeniero Civil)Los taludes constituyen estructuras fundamentales para la construcción y posterior funcionamiento de obras terrestres. Dado que este tipo de proyectos requiere de la ejecución de grandes movimientos de tierra y la formación de cortes y terraplenes, los criterios de diseño a utilizar deben balancear correctamente seguridad, plazos de ejecución, y costos. En Chile, al igual que en otras regiones sísmicas del mundo, resulta de particular importancia realizar un adecuado diseño de taludes frente a terremotos. Es así como durante las últimas décadas se han comenzado a utilizar los denominados métodos basados en desempeño, los cuales plantean que el diseño puede ser efectuado sobre la base de desplazamientos admisibles que no comprometan la estabilidad global de la estructura y permitan mantenerla operativa luego de la ocurrencia del sismo de diseño. Esta manera de abordar el problema, a diferencia de lo que sucede con el enfoque de diseño tradicional basado en fuerzas y factores de seguridad, permite cuantificar y prever los efectos que puede producir el sismo sobre la estructura; a la vez que entrega soluciones comparativamente más económicas. Una de las formas comúnmente utilizadas para estimar desplazamientos sísmicos en estructuras de tierra es hacer uso del denominado método del bloque deslizante de Newmark (1965), el cual plantea una analogía entre la masa del talud susceptible de fallar y un bloque rígido que puede deslizar sobre un plano inclinado. Los métodos de diseño actuales basados en desempeño han recogido esta idea para plantear una serie de curvas envolventes que permiten estimar los desplazamientos en un talud cualquiera como función de parámetros característicos de la solicitación sísmica y la estructura propiamente tal. En el presente trabajo se recopilan métodos basados en desempeño para determinar desplazamientos sísmicos en taludes arenosos, todos ellos desarrollados a partir de terremotos en Estados Unidos, Europa y Asia, y se utilizan registros sísmicos chilenos de 1981, 1985 y 2010 para evaluar su ajuste y aplicabilidad a las condiciones nacionales. Se utiliza la información de las estaciones acelerográficas ubicadas en suelo tipo arena a lo largo de todo el país. Para cada una de ellas se obtiene una solución de desplazamientos de referencia por medio del método del bloque deslizante de Newmark, la cual se utiliza para evaluar la bondad del ajuste de los métodos basados en desempeño analizados. A partir de los resultados obtenidos, para el diseño de taludes en arena en Chile, se sugiere el uso de las expresiones propuestas por Richards & Elms (1979), Cai & Bathurst (1996), Jibson (2007) ecuación b y Saygili & Rathje (2008). Se propone además una modificación a la ecuación c de Jibson (2007), basada en la Intensidad de Arias, para su uso en nuestro país.Slopes are key structures for both construction and operation of earth works. Given this type of projects requires the execution of important earth movements, cuts, and embankments, a design criteria that properly balance safety, deadlines, and costs has to be used. In Chile, as same as in other seismic regions of the world, it is particularly important to provide an adequate design of slopes under earthquake loading. In this sense, during the last decades, the so-called performance-based design methods have begun to be utilized. These methods are intended for design of slopes over the basis of allowable displacements, which does not compromise the overall stability of the structure and keep it operative after the occurrence of the design earthquake. In this way, and in contrast with the traditional design methods based on forces and safety factors, it is possible to quantify and anticipate the effects that the earthquake produce on the structure. In addition, a more economical design-solution can be obtained. One of the commonly used ways for estimating seismic displacements of earth structures is by making use of the sliding block method developed by Newmark (1965), who proposed an analogy between the potentially instable slope mass and a rigid block that can slide on an inclined plane. The current performance-based design methods have followed the Newmark’s idea to generate a series of design envelope curves that allows estimating the displacements on any slope as a function of the main seismic and structural parameters. In this paper, a variety of performance-based design methods for slopes on sand are collected, all of these developed from earthquakes in United States, Europe and Asia. Chilean seismic records from the earthquake events of 1981, 1985 and 2010 are used, in order to apply these methods and evaluate their fitting to the local conditions. The information obtained from the accelerographic stations located in sandy soils throughout the country is utilized. For each station, a reference displacement- solution is obtained by making use of the Newmark’s sliding block method, which is used to evaluate the quality of fit for the performance-based methods analyzed. From the results obtained, for design of slopes on sand in Chile, it is suggested to use the expressions proposed by Richards & Elms (1979), Cai & Bathurst (1996), Jibson (2007) equation b and Saygili & Rathje (2008). In addition, the equation c by Jibson (2007), based on Arias intensity, is modified for its use in our country

Different Secondary Metabolite Profiles of Phylogenetically almost Identical Streptomyces griseus Strains Originating from Geographically Remote Locations

As Streptomyces have shown an outstanding capacity for drug production, different campaigns in geographically distant locations currently aim to isolate new antibiotic producers. However, many of these newly isolated Streptomyces strains are classified as identical to already described species. Nevertheless, as discrepancies in terms of secondary metabolites and morphology are possible, we compared two Streptomyces strains with identical 16S rRNA gene sequences but geographically distant origins. Chosen were an Easter Island Streptomyces isolate (Streptomyces sp. SN25_8.1) and the next related type strain, which is Streptomyces griseus subsp. griseus DSM 40236T isolated from Russian garden soil. Compared traits included phylogenetic relatedness based on 16S rRNA gene sequences, macro and microscopic morphology, antibiotic activity and secondary metabolite profiles. Both Streptomyces strains shared several common features, such as morphology and core secondary metabolite production. They revealed differences in pigmentation and in the production of accessory secondary metabolites which appear to be strain-specific. In conclusion, despite identical 16S rRNA classification Streptomyces strains can present different secondary metabolite profiles and may well be valuable for consideration in processes for drug discover

El complejo de la estación central de ferrocarriles: construcción, ubicación y relación con el espacio capitalino (1856-1864)

Desde la segunda mitad de la década de 1850, se comenzó en la ciudad de Santiago la construcción y posterior puesta en funciones del Complejo Estación Central de los ferrocarriles. Así, la ciudad no sólo amplió su radio urbano hacia el poniente, sino que también se ubicó en aquel sector el centro neurálgico de la actividad ferroviaria, debido a la convergencia de los dos trayectos ferroviarios más importantes del país. A partir del análisis de fuentes documentales diversas como el archivo del Ministerio del Interior, las Actas del Congreso Nacional, Informes de las Empresas de Ferrocarriles y el periódico El Ferrocarril, se pretende reconstruir uno de los hitos más importantes de la historia ferroviaria nacional. El arribo del ferrocarril a la capital, no sólo marcó la expansión de este medio de transportes, sino además la integración de un sector hasta ese momento periférico del área urbana, que con el paso de las décadas se posicionó como un punto esencial dentro del tramado urbano de la capital de Chile

Génesis y desarrollo de una política ferroviaria: antecedentes y opiniones sobre la construcción de ferrocarriles en el valle central del Chile a mediados del siglo XIX

Towards the end of the 1840s, Chile began to discuss in the high public and private spheres, about the installation of railway lines in the central area of the country and its potential effects on the productive apparatus and the commercial system. From the possible expectations, various opinions, ideas and judgments were presented, both in favor and against the railroad. It was, in the National Congress, the instance where debates and discussions took place, which finally became the legaladministrative framework that governed the future railway projects of the Chilean central valley. In this sense, and as a result of which there was not a single trial that prevailed over the railroad, the objective of this work is to be an approximation to the feelings that were pointed out around the subject under discussion by the mid-19th century. The documentary base corresponds to the Proceedings of the National Congress, from where the expositions made by different parliamentarians were obtained, and which were complemented by memoirs and ministerial reports that gave account of the contexts in which the genesis of the railway policy was developed.Hacia finales de la década de 1840, se comenzó en Chile a discutir en las altas esferas públicas como privadas, sobre la instalación de tendidos ferroviarios en la zona central del país y, sus potenciales efectos sobre el aparato productivo y el sistema comercial. A partir de estas expectativas, se expusieron diversas opiniones, ideas y juicios, tanto a favor como en contra del ferrocarril. Fue, en el Congreso Nacional, la instancia en donde se desarrollaron los debates y las discusiones, que finalmente se convirtieron en el marco jurídico-administrativo que rigió los futuros proyectos ferrocarrileros del valle central chileno. En este sentido, y producto de que no hubo un único juicio que primó acerca del ferrocarril, el objetivo de este trabajo es constituirse en una aproximación a las opiniones que se señalaron en torno al tema en discusión para mediados del siglo XIX. La base documental corresponde a las Actas del Congreso Nacional, desde donde se obtuvieron las exposiciones hechas por distintos parlamentarios, y que fueron complementadas por memorias e informes ministeriales que dieron cuenta de los contextos en que se desenvolvió la génesis de la política ferroviaria

High diversity and novelty of Actinobacteria isolated from the coastal zone of the geographically remote young volcanic Easter Island, Chile

Easter Island is an isolated volcanic island in the Pacific Ocean. Despite the extended knowledge about its origin, flora, and fauna, little is known about the bacterial diversity inhabiting this territory. Due to its isolation, Easter Island can be considered as a suitable place to evaluate microbial diversity in a geographically isolated context, what could shed light on actinobacterial occurrence, distribution, and potential novelty. In the present study, we performed a comprehensive analysis of marine Actinobacteria diversity of Easter Island by studying a large number of coastal sampling sites, which were inoculated into a broad spectrum of different culture media, where most important variations in composition included carbon and nitrogen substrates, in addition to salinity. The isolates were characterized on the basis of 16S ribosomal RNA gene sequencing and phylogenetic analysis. High actinobacterial diversity was recovered with a total of 163 pure cultures of Actinobacteria representing 72 phylotypes and 20 genera, which were unevenly distributed in different locations of the island and sample sources. The phylogenetic evaluation indicated a high degree of novelty showing that 45% of the isolates might represent new taxa. The most abundant genera in the different samples were Micromonospora, Streptomyces, Salinispora, and Dietzia. Two aspects appear of primary importance in regard to the high degree of novelty and diversity of Actinobacteria found. First, the application of various culture media significantly increased the number of species and genera obtained. Second, the geographical isolation is considered to be of importance regarding the actinobacterial novelty found

Antitumor Anthraquinones from an Easter Island Sea Anemone: Animal or Bacterial Origin?

The presence of two known anthraquinones, Lupinacidin A and Galvaquinone B, which have antitumor activity, has been identified in the sea anemone (Gyractis sesere) from Easter Island. So far, these anthraquinones have been characterized from terrestrial and marine Actinobacteria only. In order to identify the anthraquinones producer, we isolated Actinobacteria associated with the sea anemone and obtained representatives of seven actinobacterial genera. Studies of cultures of these bacteria by HPLC, NMR, and HRLCMS analyses showed that the producer of Lupinacidin A and Galvaquinone B indeed was one of the isolated Actinobacteria. The producer strain, SN26_14.1, was identified as a representative of the genus Verrucosispora. Genome analysis supported the biosynthetic potential to the production of these compounds by this strain. This study adds Verrucosispora as a new genus to the anthraquinone producers, in addition to well-known species of Streptomyces and Micromonospora. By a cultivation-based approach, the responsibility of symbionts of a marine invertebrate for the production of complex natural products found within the animal’s extracts could be demonstrated. This finding re-opens the debate about the producers of secondary metabolites in sea animals. Finally, it provides valuable information about the chemistry of bacteria harbored in the geographically-isolated and almost unstudied, Easter Island

Data publication: Learning from nature: recovery of rare earth elements by the extremophilic bacterium Methylacidiphilum fumariolicum

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