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Colección institucional

Tesis y artículos académicos

En esta colección encontrarás los productos de investigación académica de beneficiarios de COLFUTURO y Fulbright, en diversas disciplinas, como arte, biología, administración e ingeniería.

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    • Otros
    • 1225 Tesis
    • 5 Audios
    • 820 Artículos
  • Creada el:
    • 15 de Julio de 2019
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Creador Biblioteca Virtual Banco de la República
Imagen de apoyo de  First tracking of declining Caspian terns Hydroprogne caspia breeding in the Baltic Sea reveals high migratory dispersion and disjunct annual ranges as obstacles to effective  conservation

First tracking of declining Caspian terns Hydroprogne caspia breeding in the Baltic Sea reveals high migratory dispersion and disjunct annual ranges as obstacles to effective conservation

Por: Cristina; Lötberg Rueda Uribe | Fecha: 2021

Abstract: The conservation of migratory species poses significant challenges that may be countered by detailed knowledge about the sites used by migrants throughout the annual cycle. We present the rst GPS-tracking data on the migration of declining Caspian terns Hydroprogne caspia breeding in the Baltic Sea. For 39 Caspian terns from colonies along a latitudinal gradient from 57 to 65°N, we identified key migratory routes, stopovers and wintering areas. In autumn these seabirds migrated using coastal and freshwater stopovers along six routes to reach their wintering areas across the Sahel, the Nile River Basin and the southern Iberian Peninsula. In spring, adults returned to the breeding grounds in the Baltic using a time optimizing strategy by reducing time at stopover by 78%, whereas most subadults remained sedentary and some performed only partial return migrations. Of the stopover sites used in both seasons, 58% are protected and have a reported management plan. Conservation strategies in wintering areas, stopover sites that are not protected or had not been previously recognized, and the inclusion of the species in important migratory yways across Europe and Africa will be important to prevent further population declines of a species that depends on aquatic habitats.
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First tracking of declining Caspian terns Hydroprogne caspia breeding in the Baltic Sea reveals high migratory dispersion and disjunct annual ranges as obstacles to effective conservation

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Imagen de apoyo de  Is the world repeating itself? = ¿Está el mundo repitiéndose?

Is the world repeating itself? = ¿Está el mundo repitiéndose?

Por: Daniel Ruiz Romero | Fecha: 2021

Abstract: On hearing about the massacre that took place in 1928 in Ciénaga, Colombia; Úrsula – a character from One Hundred Years of Solitude – wonders if history keeps repeating itself. Her concern, voiced in in the 1978 novel by Nobel Prize laureate Gabriel García Márquez, is entirely valid today, 500 years after the arrival of the first Europeans in America and nearly a hundred years after the massacre at the banana plantations. Nowadays, it’s not the Spanish crown or the United Fruit Company that are changing the sociopolitical panorama of Latin America, but technological giants form Silicon Valley colonizing the countries of the global south by creating dependency on their digital platforms. Three cases of colonialism in Latin America are examined to understand the evolution of the colonial system that has always been surrounded by a halo of inevitability. The first chapter, In the Name of God, studies colonialism as a system established after the arrival of the Spanish in America. The second chapter, In the Name of Progress, examines the colonial logic behind the United Fruit Company’s actions in South America and the Caribbean. The third chapter, In the Name of Information, reflects on current forms of colonialism through connectivity initiatives led by surveillance capitalist companies like Facebook. As a conclusion, an alternative to the colonial narrative is proposed, which consists of an emancipatory discourse, based on the texts of the Brazilian Oswald Andrade and Oswaldo Costa and Italian philosopher Franco ‘Bifo’ Berardi. Resumen: Al enterarse de la masacre ocurrida en 1928 en Ciénaga, Colombia; Úrsula, un personaje de "Cien Años de Soledad", se pregunta si la historia sigue repitiéndose. Su preocupación, expresada en la novela de 1978 del premio Nobel Gabriel García Márquez, es plenamente válida hoy, 500 años después de la llegada de los primeros europeos a América y casi cien años después de la masacre de las bananeras. Hoy en día, no es la corona española, ni la United Fruit Company, las que están cambiando el panorama sociopolítico de América Latina, sino los gigantes tecnológicos de Silicon Valley que colonizan los países del sur global creando dependencias a sus plataformas digitales. Para comprender la evolución del sistema colonial que siempre ha estado rodeado de un halo de inevitabilidad, se examinan tres casos de colonialismo en América Latina. El primer capítulo, "En nombre de Dios", estudia el colonialismo como un sistema establecido tras la llegada de los españoles a América. El segundo capítulo, "En nombre del progreso", examina la lógica colonial detrás de las acciones de la United Fruit Company en América del Sur y el Caribe. El tercer capítulo, "En nombre de la información", reflexiona sobre las formas actuales de colonialismo a través de iniciativas de conectividad lideradas por empresas que abogan por el capitalismo de vigilancia como Facebook. Como conclusión, se propone una alternativa a la narrativa colonial, que consiste en un discurso emancipatorio, basado en los textos del brasileño Oswald Andrade y Oswaldo Costa y del filósofo italiano Franco ‘Bifo’ Berardi.
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Is the world repeating itself? = ¿Está el mundo repitiéndose?

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Imagen de apoyo de  Parque Temporal Piscina Romano, Città Studi, Milán = Parco Temporaneo Piscina Romano, Città Studi, Milano

Parque Temporal Piscina Romano, Città Studi, Milán = Parco Temporaneo Piscina Romano, Città Studi, Milano

Por: Yina Licet Mora Ramos | Fecha: 2014

Resumen: La Piscina Romano es una piscina al aire libre tradicional de la ciudad de Milán, construida en el año 1920, que funciona solo en los meses de verano y luego se vacía y se cierra durante el resto del año. Mi objetivo ha sido crear una instalación de parque temporal dentro del área de la piscina, para volverla útil en meses en que está vacía. El complejo balnear está ubicado en un área central de la ciudad de Milán, en una zona residencial y predominantemente universitaria, con una importante presencia del de Milán. La Piscina Romano tiene un área de 17.400m2 aprox. y sólo un 29% de su área es funcional durante todo el año. El estado actual de este complejo balnear es un espacio totalmente fragmentado y desarticulado, de áreas abandonadas y sub-utilizadas, que quise integrar y refuncionalizar dentro del proyecto de parque temporal. La idea de crear un parque surgió con la intención de ampliar el parque de juegos de la piscina Romano hacia la piscina grande. Partiendo del concepto “La piscina que se convierte en parque”, luego también hice lo contrario, es decir, “el parque que se convierte en piscina”, esto quiere decir que el área de juego actual se ha convertido en una especie de piscina metafórica. De esta manera, los integré, pero también creé una ambigüedad entre uno y otro, disolviendo los límites entre ellos y produciendo un único espacio recreativo, dentro de una paradoja: no un parque y una piscina, sino un parque acuático y recreativo. Diseñé una obra de street painting en el suelo de todo el complejo para crear una metáfora. Los gráficos del suelo inundaron todo el balneario e integraron todas las piezas. En el edificio de vestieres decidí en cambio, crear un parque cubierto para permitir que la dinámica social alrededor del área de juegos al aire libre continúe desarrollándose a pesar del frío, y para que los niños, padres y ancianos tengan un lugar de encuentro cómodo en los meses más fríos del año. Por otro lado, quería retomar el complejo escultórico “Los Baños Misteriosos” de Giorgio De Chirico, actualmente ubicado en la Trienal de Milán, trasladándolo a la Piscina Romano como parte del proyecto de parque temporal, agregando valor al parque. Finalmente, lo que había imaginado como un parque de estación se convirtió en un dispositivo permanente. Las esculturas adquirieron un papel protagónico y el proyecto se convirtió en un escenario para exhibirlas. El resultado es una especie de parque acuático y recreativo, pero con esculturas valiosas.
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Parque Temporal Piscina Romano, Città Studi, Milán = Parco Temporaneo Piscina Romano, Città Studi, Milano

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Imagen de apoyo de  Las Malinches vs The Great Social Network = Las Malinches versus la gran red social

Las Malinches vs The Great Social Network = Las Malinches versus la gran red social

Por: Daniel; Arias Ruiz Romero | Fecha: 2021

Abstract: Las Malinches vs the Great Social Network’ is a visual album by a Colombian music band, specially put together for this graduation project. The soundtrack narrates the group’s formation process, in response to the connectivity programs introduced by Facebook in the global south. The album portrays the band’s state of paralysis in the face of these connectivity programs. Finally, the album celebrates existing communication systems that could present a less corporate alternative to the American platform. The album contains videos that contextualize and satirize Facebook’s charitable endeavors and additionally, it includes original music that acts as counter narrative to Zuckerberg’s neoliberal and possibly neocolonial gospel. The electro-cumbia songs, written specifically for this graduation project, question the inevitable position of Facebook. They mix local rhythms with western sounds and thus propose a new musical language in which both influences merge. Orality is used as a tool for knowledge creation, a fundamental practice in South American cultures. The visual album is distributed by means of a raspberry pi, aiming to show the public that there are alternatives to share content in hybrid spaces where physicality is as important as digital connectivity. This allows us to think about the ‘internet outside the internet’. It works as the starting point for the creation of community networks that, in the end, demonstrate how the narratives of the large tech-companies might be forceful, but they are certainly not inevitable. Resumen: ‘Las Malinches vs the Great Social Network’ es un álbum visual de una banda de música colombiana, elaborado especialmente para este proyecto de graduación. La banda sonora narra el proceso de formación del grupo, en respuesta a los programas de conectividad introducidos por Facebook en el sur global. El álbum retrata el estado de parálisis de la banda frente a estos programas de conectividad. Finalmente, el álbum celebra los sistemas de comunicación existentes que podrían presentar una alternativa menos corporativa a los de la plataforma estadounidense. El álbum contiene videos que contextualizan y satirizan los esfuerzos caritativos de Facebook y, además, incluye música original que actúa como contranarrativa del evangelio neoliberal y posiblemente neocolonial de Zuckerberg. Las canciones de electro-cumbia, escritas específicamente para este proyecto de graduación, cuestionan la inevitable posición de Facebook. Mezclan ritmos locales con sonidos occidentales y así, proponen un nuevo lenguaje musical en el que se fusionan ambas influencias. La oralidad se utiliza como herramienta para la creación de conocimiento, retomando esta práctica fundamental de las culturas sudamericanas. El álbum visual se distribuye mediante una raspberry pi, con el objetivo de mostrar al público que existen alternativas para compartir contenidos en espacios híbridos donde la fisicalidad es tan importante como la conectividad digital. Esto nos permite pensar en "Internet fuera del Internet". El proyecto funciona entonces como el punto de partida para la creación de redes comunitarias que, al final, demuestran cómo las narrativas de las grandes empresas tecnológicas pueden ser poderosas, pero ciertamente no son inevitables.
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Imagen de apoyo de  A critical Analysis on "Purgare": One of Many Colombian Stories on Social Cleansing

A critical Analysis on "Purgare": One of Many Colombian Stories on Social Cleansing

Por: Carlos Manuel Saavedra Parra | Fecha: 2019

Abstract: Every year, thousands are selectively killed and displaced in social cleansing campaigns in Colombia announced in publicly-posted pamphlets. Also known as the “black hand”, the selective killings have become a hallmark of the country’s poorest neighborhoods. Often perpetrated by neighbors, under the auspices of paramilitary groups and with the complicity or even participation of local police, these murders are touted as the necessary procedures of order in places where official justice cannot reach. Drug users, petty criminals, LGBTQ folk and especially trans women, are the preeminent targets of such campaigns. Already largely labeled as deviant or marginal, those whose lives are threatened and who dare make official complaints are dismissed by those institutions tasked with their safety. Purgare invites a consideration of social cleansing not from the perspective of the violence of its perpetrators, but through those who stand in resistance against it. This project accompanies a group of trans women who, faced with the extra-legal and legal dismissal of their lives, take recourse to magic to protect themselves and to reassert a modicum of agency. Bringing together photojournalism, anthropology, and artistic representation, the series and essay inhabits the magically real space created by these women, illuminating the powers they conjure in the worlds they create. Purgare stages the journeys of transformation crafted by these self-styled witches through their manipulations of plants and energies to forge lasting and powerful connections between new peoples and novel worlds. Purgare is imagined between disciplines and knowledges in an effort to expand the bounds of story-telling traditionally produced about violence. It builds a space in which those who struggle against structural violence can meet to create new representations of themselves and together weave novel images of power and possibility. Based on the stories of Stefania Grajales, Paola Caicedo and Catalina Lozano.
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A critical Analysis on "Purgare": One of Many Colombian Stories on Social Cleansing

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Imagen de apoyo de  Biluminescence of purely organic materials: fundamentals and applications in optical sensing

Biluminescence of purely organic materials: fundamentals and applications in optical sensing

Por: Caterin Yojana Salas Redondo | Fecha: Ca. 2017

Abstract: The property of an organic molecule able to emit light efficiently from both their singlet and triplet excited states is called biluminescence. This dual state emission, particularly at room temperature, is difficult to achieve by purely organic molecules. It is possible only if the competitive thermal decay is suppressed effectively, enhancing the yield from the triplet state (i.e. phosphorescence) in addition to the conventional fluorescence. Biluminescence was identified in a simple host:guest system in which the biluminophore (i.e. an organic molecule showing biluminescence) NPB [N,N’-di(naphtha-1-yl)-N,N’- diphenyl-benzidine] is embedded in a rigid matrix, for example, the polymer PMMA [poly(methyl methacrylate)]. This system is unique not only due to the dual state emission, having fluorescence and phosphorescence emissions at 425nm and 530nm, respectively, but also because the large range of exciton lifetimes is extended up to nine orders of magnitude between nanosecond fluorescence and second phosphorescence. Up to date, efforts have been placed exclusively in the research of room temperature phosphorescence (RTP), although fluorescence can be observed from these systems as well. Therefore, the aim of this thesis was the investigation of the fundamental photophysical processes and characteristics of biluminescent organic molecules, in addition to their usage in promising applications as it will be described next. For instance, the most used approach for oxygen sensing is based on quenching of luminescent excited states, following a scheme of optical monitoring, i.e. correlating luminescence over-time data with oxygen concentrations. However, regardless whether one pursues fluorescence or phosphorescence quenching, they share a common drawback: They cannot monitor the effect of sample degradation due to extensive light exposure. In fact, one cannot distinguish between oxygen having penetrated the film and quenched the luminescence, or the sample being degraded over time due to e.g. photobleaching of the emitting molecules. The former represents an issue, especially for build-in applications. Now herein, it was proposed to use biluminescence to exclude degradation processes from oxygen sensing data evaluation, through a simple fluorescence-to-phosphorescence intensity ratio. This can be achieved, because it was proven here that the fluorescence is not directly quenched by oxygen, whereas the long-lived RTP is sensitive to it. Therefore, the fluorescence acts as self-referencing in a biluminescent sensor, which serves as an alternative solution to monitor oxygen concentrations. Additionally, the integration of the sensor into optoelectronic devices is considered as a potential future direction. Furthermore, it was revealed in this thesis that the difference in exciton lifetime yields to a significant limitation of luminescence efficiency, because of exciton accumulation under continuous illumination, causing bimolecular processes like singlet-triplet and triplet-triplet annihilation (STA and TTA, respectively), as well as optical saturation. All those processes occur already at moderate excitation intensities. It was demonstrated through sample engineering and oxygen quenching experiments, that the triplet exciton density can be controlled over several orders of magnitude, allowing to study exciton interactions between singlet and triplet manifolds. Consequently, the presented biluminescent system represents an illustrative role model to study excitonic effects in organic molecules. For example, in organic light-emitting diode materials, where the aforementioned effects i.e. STA, TTA and saturation, are application relevant but much more difficult to investigate. Mainly because light emission can be observed only from one state, instead of both states like in biluminescence.
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Biluminescence of purely organic materials: fundamentals and applications in optical sensing

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Imagen de apoyo de  Interplay of Fluorescence and Phosphorescence in Organic Biluminescent Emitters

Interplay of Fluorescence and Phosphorescence in Organic Biluminescent Emitters

Por: Caterin Yojana; Kleine Salas Redondo | Fecha: 2017

Abstract: Biluminescent organic emitters show simultaneous fluorescence and phosphorescence at room temperature. So far, the optimization of the room-temperature phosphorescence in these materials has drawn the attention of research. However, the continuous-wave operation of these emitters will consequently turn them into systems with vastly imbalanced singlet and triplet populations, which is due to the respective excited-state lifetimes. This study reports on the exciton dynamics of the biluminophore NPB (N,N′-di(1-naphthyl)-N,N′-diphenyl-(1,1-biphenyl)-4,4-diamine). In the extreme case, the singlet and triplet exciton lifetimes stretch from 3 ns to 300 ms, respectively. Through sample engineering and oxygen quenching experiments, the triplet exciton density can be controlled over several orders of magnitude, allowing us to study exciton interactions between singlet and triplet manifolds. The results show that singlet−triplet annihilation reduces the overall biluminescence efficiency already at moderate excitation levels. Additionally, the presented system represents an illustrative role model to study excitonic effects in organic materials.
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Interplay of Fluorescence and Phosphorescence in Organic Biluminescent Emitters

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Imagen de apoyo de  Simultaneous fluorescence and phosphorescence from organic molecules

Simultaneous fluorescence and phosphorescence from organic molecules

Por: Caterin Yojana; Reineke Salas Redondo | Fecha: 2015

Diluting organic molecules in a polymer matrix material suppresses non-radiative behavior, leading to biluminescence, wherein light is emitted efficiently from both singlet and triplet states. In summary, biluminescence has developed into a thoroughly optimized and unique emissive system. Among the characteristics obtained through this system, the most significant is the ability of biluminophores to offer direct access to the radiative states of both spin manifolds (singlets and triplets) in organic molecules without the requirement for special or complex material combinations. As a result, an exciton is given the chance to re-emit its energy, regardless of its initial state. In future work, we intend to increase the toolset of organic biluminophores by screening materials to determine the structure-property relationships behind persistent phosphorescence, and to identify molecular building blocks that are suitable for the development of future materials. In addition, we will intensify our exploration of biluminescence for future applications (e.g., sensing).
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Simultaneous fluorescence and phosphorescence from organic molecules

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Imagen de apoyo de  Life cycle assessment of perovskite on silicon tandem PV modules at industrial scale

Life cycle assessment of perovskite on silicon tandem PV modules at industrial scale

Por: Caterin Yojana; Blanco Salas Redondo | Fecha: 2020

Abstract: For the first time a comprehensive life cycle assessment (LCA) is reported of a large-area perovskite/Si tandem photovoltaic (PV) module of about 2 m², with an assumed power conversion efficiency of 30%, 30 years lifetime and an annual degradation of 0.5%, manufactured in a 1 GW production plant. By means of the LCA method, we calculate the contribution to the International Reference Life Cycle Data System (ILCD) impact categories associated with a perovskite/Si tandem PV system compared with a passivated emitter and rear cell (PERC) used as reference. We consider a functional unit of 1 kWh of generated direct current electrical energy from the tandem module over its lifetime. It was found that the most significant environmental hotspots are the silicon wafer production and the balance of system (BOS), especially the mounting system, inverter and electric installation. Overall, the impact contributions to the environment caused by the perovskite sub-module are below 1% throughout all the ILCD categories in focus: climate change, freshwater ecotoxicity, water resource depletion and human toxicity. Even the contribution of lead to human toxicity is just about 0.01%. For all the impacts assessed, the perovskite/Si tandem shows a decrease of between 17-20% of the contributions to each impact category compared to the PERC-module based reference PV system, if the Si bottom sub-module has an initial cell efficiency of at least 22% with 1% cell-to-module (CTM) loss, and the perovskite top sub-module has a minimum initial cell efficiency of 18% with at most 5% CTM loss and a transmittance near IR region larger than 80%. The key result found in this work is the relevance of the performance and reliability of the PV system to achieve lower environmental impacts. A comparison between optimistic, realistic, and pessimistic scenarios was performed to investigate this matter: in the worst-case scenario, the environmental impact of the PV tandem system would have a general 50% increase throughout all ILCD impact categories against the realistic case, whereas in the optimistic one, the results suggest a reduction of 46% to the global impact contributions, compared to the realistic scenario.
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Life cycle assessment of perovskite on silicon tandem PV modules at industrial scale

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Imagen de apoyo de  History

History

Por: María Catalina; Díaz Pabón Jiménez Jiménez | Fecha: 2019

Abstract: The history of Colombia has been defined by the paradox of the coexistence of violence and economic growth. While the economy of the country has grown almost uninterruptedly since the middle of the 20th century, in 2019 the state was still not fully capable of reasserting its presence nor of providing justice or security for all of its citizens across its territory. This chapter analyses the paradox of the coexistence of armed violence and economic growth in Colombia, in which parts of the elite sections of the country benefit by the lack of security and justice. Violence is good for business, although not good for statehood.
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History

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