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Por: Laura López Estupiñán | Fecha: 11/08/2021

Las evidencias arqueológicas en la cordillera de los Andes muestran una diversidad de alimentos adaptados y consumidos por sus pobladores. En Boyacá la investigación Alimentos prehispánicos, alimentos promisorios, realizada por el Grupo Interdisciplinario de Investigaciones Arqueológicas e Históricas de la Universidad Pedagógica y Tecnológica de Colombia (uptc), convenio Colciencias (2011- 2013), estudió los usos y saberes de diez alimentos identificados previamente en columnas de polen, fitolitos, almidones, carbones y relatos etnohistóricos. Para este artículo serán priorizados la Oxalis tuberosa, el Tropaeolum toberosum y el Ullucus tuberosus, por tratarse de alimentos con prácticas agrícolas particulares que evidencian relaciones recíprocas en la siembra, cosecha y consumo, las cuales serán descritas en innumerables recuerdos, formas de custodia y descripciones contenidas de sentires, apegos, cuidados y saberes en torno a la práctica del agricultar la tierra.

Fuente: Icanh - Arqueología y Patrimonio Formatos de contenido: Artículos

Temas:
Otros

Imagen de apoyo de AlN film deposition as a semiconductor device

Por: Jaime Andrés; Aperador Pérez Taborda | Fecha: 2013

AlN films were deposited by pulsed laser deposition (PLD) using an Nd: YAG laser (?= 1064 nm). The films were deposited in a nitrogen atmosphere as working gas; the cathode was an aluminium high purity (99.99%) target. The films were deposited using 7 J/cm2 laser fluence for 10 minutes on silicon (100) substrates. The working pressure was 9x10-3 mbar and the substrate temperature was varied from 200 C to 630 C. The thickness measured by profilometer was 150 nm for all films. Moreover, surface acoustic wave (SAW).

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros

Imagen de apoyo de The Influence of Algal Biomass on Tracer Experiments in Maturation Ponds

Por: Miller Alonso; Mara Camargo Valero | Fecha: 2007

Tracer experiments are of concern to wastewater treatment engineers and researchers because of the importance of determining hydraulic regimes and retention times in wastewater treatment units. In this work, a pilot-scale maturation waste stabilisation pond (WSP) was spiked with Rhodamine WT, in order to determine how suspended organic matter would interfere with its performance as a tracer in a domestic wastewater treatment unit which had a high content of suspended algal biomass. A primary maturation pond was spiked in three separate runs with different levels of algae (high, medium and low), with a known amount of Rhodamine WT (20% w/v); the tracer was measured in the pond effluent in real time every 20 min for 3? (the theoretical retention time, ? = 17 days). Algal biomass was monitored weekly from influent, column and effluent water samples by chlorophyll-a determination. The results show that algal biomass has a strong influence on the behaviour of Rhodamine WT as a tracer and therefore the hydraulic characteristics calculated from tracer curves may be affected by tracer adsorption on suspended organic matter.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros
Ingeniería

Imagen de apoyo de Philosophy and poetry. Architecture and art: a place between

Por: Ivan Fernando Chaparro Mora | Fecha: 2012

By outdoing the etymological characterization of philosophy and poetry, the article outlines a comparison between architecture and art as disciplines that inform each other complexly, allowing drawing reflections about the effect the historical continuum has on material production, through the passage of time and into the traces of history. The role of the critic here is compared to that of the philosopher, as the one who gets informed from the realm of art; such relation is illustrated with the work of the German philosopher Walter Benjamin and the French poet Charles Baudelaire, as a precise dialectical account of the socio-cultural philosophy of history, during the XIX century in Paris.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros
Arte

Imagen de apoyo de The transport sector and the CDM: long-term sustainable development? – Transmilenio’s experience

Por: Guillermo Umaña Restrepo | Fecha: 2015

The Kyoto Protocol Clean Development Mechanism (CDM) is currently the only United Nations Framework Convention on Climate Change (UNFCCC) market mechanism that includes transport projects in developing countries. This mechanism has the dual objective of promoting sustainable development and contributing to green-house-gas emission reductions. However, transportation is currently a niche sector within the CDM due to the small number of transport projects registered under it. This is despite transportation being one of the sectors with the fastest growth-rate of greenhouse-gas emissions in the developing world. This paper examines the limitations of CDM-registered transport projects to achieve long-term sustainable development outcomes through the CDM. The experience of project ‘TransMilenio Phase II – IV’ in Bogotá (Colombia) serves to argue that CDM registration requirements of Additionality and Fixed-Term Crediting may be detrimental to achieving these outcomes through the CDM. Thus an opportunity exists to increase the significance of the transport sector within the international climate change regime through a dedicated ‘Sustainable Development Package for Transport’ in future agreements.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros
Ciencias sociales

Imagen de apoyo de A therapeutically viable photo-activated manganese-based CO-releasing molecule (photo-CO-RM)

Por: David Esteban; Fairlamb Sanín Peña | Fecha: 2012

A new class of photochemically-activated CO-releasing molecule (photo-CO-RM), based on a Mn(CO)4(C^N) system, is reported in this study. Three CO molecules are released per CO-RM molecule. Complex 3 is a fast releaser, thermally stable in the dark and a viable therapeutic agent.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros

Imagen de apoyo de Traditional Investment Tools Using Backtesting Simulations: The Case of Colombian Stock Market for the Period 2007-2013

Por: Orlando Enrique; Vecino Arenas Contreras Pacheco | Fecha: 2016

This study intends to prove the viability of the mean-variance portfolio methodology introduced by Harry Markowitz in 1950 as a traditional concept that modern retail investors could use to improve the performance of their investments, over and above that offered by the average actively managed or index equity fund. Likewise, represents a final dossier with several outputs obtained by the design and running of an optimization model, which was developed by using basic financial concepts. This algorithm which is based on a back testing analysis, simulated four investment strategies by taking into account historical data on the Colombian stock market. From this application, recommended portfolios for each strategy are obtained and ran for the period between 2007 and 2013, which are compared in terms of return and risk to the most representative Colombian stock index (IGBC) behavior. Results achieved indicate that the designed algorithm is effective, yet demonstrate a more superior integral performance than the market. Its main contribution is the model’s potential use for supporting actual investment decisions. It is believed there is sufficient evidence to support the use of traditional concepts and financial tools like the mean-variance optimization as a valid, value-adding mechanism for investors.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros
Economía

Imagen de apoyo de Enhanced Phosphorus Removal in a Waste Stabilization Pond System With Blast Furnace Slag Filters

Por: Miller Alonso; Mara Camargo Valero | Fecha: 2007

In this work a tertiary horizontal-flow blast furnace slag (BFS) filter was tested for phosphorus removal under laboratory and field conditions. Laboratory experiments were conducted in a bench-scale BFS filter for phosphorus adsorption capacity at equilibrium conditions using P-spiked water. On-site, the performance of a pilot-scale BFS filter was monitored for phosphorus removal from the final effluent of a pilot-scale WSP system located in Esholt (Bradford, UK), which comprises a primary facultative pond and a secondary aerated rock filter (ARF) in series. Adsorption capacity (q) results showed that BFS has high affinity for inorganic P species and it can remove up to 30 g P/kg BFS; however, q values are strongly dependent on the initial P concentration. The pilot-scale BFS filter tested on-site performed better for longer (<2 mg P/L) than the laboratory-scale filter, even though despite the latter received the same hydraulic and P loadings (1.8 m3/m3 d and 18 g P/m3 d, respectively). Both the laboratory and field results showed that BFS filters are an appropriate low-cost technology to upgrading small wastewater treatment systems for phosphorus removal.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros
Ingeniería

Imagen de apoyo de The soviet and russian military-industrial complex: different approaches, common conclusions

Por: Andrés Eduardo Fernández Osorio | Fecha: 2013

This article aims to perform a comparative analysis of several publications on a particular topic: The Soviet and Russian Military-Industrial Complex. It examines the results of different surveys and, specifically, addresses how several authors have studied the social phenomena. Moreover, it analyses the methods that they used to develop useful discernments with limited documental resources. Finally, it offers conclusions about the common findings and the possible application of such methods on future research.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros
Ciencias sociales

Imagen de apoyo de Deposition pressure effect on chemical, morphological and optical properties of binary Al-nitrides structural and optical properties of compounds (AIN, GaN, InN)

Por: Jaime Andrés; Caicedo Pérez Taborda | Fecha: 2015

Aluminum nitride films (AlN) were produced by Nd:YAG pulsed laser (PLD), with repetition rate of 10 Hz. The laser interaction on Al target under nitrogen gas atmosphere generates plasma which is produced at room temperature with variation in the pressure work from 0.39 Pa to 1.5 Pa thus producing different AlN films. In this sense the dependency of optical properties with the pressure of deposition was studied. The plasma generated at different pressures was characterized by optical emission spectroscopy (OES). Additionally ionic and atomic species from the emission spectra obtained were observed. The plume electronic temperature has been determined by assuming a local thermodynamic equilibrium of the emitting species. Finally the electronic temperature was calculated with Boltzmann plot from relative intensities of spectral lines. The morphology and composition of the films were studied using atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy analysis (XPS) and Raman Spectroscopy. The optical reflectance spectra and color coordinates of the films were obtained by optical spectral reflectometry technique in the range from 400 nm to 900 nm. A clear dependence in morphological properties and optical properties, as a function of the applied deposition pressure, was found in this work which offers a novel application in optoelectronic industry.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros