Engineered barriers are used in the containment of hazardous materials and are usually a composite of compacted clayey soil and a synthetic membrane. Containment elements such as landfill liners should be designed to control or prevent leachate migration or groundwater ingress. Engineering specifications for a compacted clay liner are based mainly in a hydraulic conductivity less than 10-9 m/s and the need for stability during construction and operation of the landfill. Sandbentonite mixtures are often used as a barrier material. The addition of relatively small amounts of bentonite (5-15%) can improve the performance of a granular material providing both a low permeability and an enhanced mechanical stability.However not all the possible compaction conditions produce a low permeability and mechanically stable material. Changes in water content after compaction can cause swelling or collapse depending on the stress and suction conditions before the water content change occurs. A laboratory investigation of the swelling-collapse behaviour of compacted mixtures of Sand-bentonite has been undertaken. Compaction and suction characteristics were established. The suction and volume change characteristics were investigated through a series of oedometer tests. The central part of the experimental programme focused on the detailed investigation of the processes of swelling and collapse during controlled wetting.To do this, a significant number of modifications were required to the existing apparatus. Fabric studies including Environmental Scanning Electron Microscopy and Mercury Intrusion Porosimetry were also undertaken. Intrinsic behaviour and the relationship between suction and water content were comprehensively studied. A parametric study of the influence of bentonite content and sand grading was also undertaken. The results are presented and analysed. Recommendations for future research are made.

The series of studies accomplished and compiled in the present thesis had as a main objective the evaluation of the suitability of the Colombian Artemia franciscana for the aquaculture industry. Further, an evaluation of six newly reported populations (Salina Cero, Kangarú, Tayrona, Bahía Hondita, Pusheo and Warrego) is included. In addition to the description of biotypes, physicochemical parameters were recorded for each population studied. The habitats where Artemia has actually been registered in Colombia are of marine (thalassohaline) origin, thus they are sodium and chloride rich. The application of biometric tools to determine possible cyst and nauplius size differences among the different Colombian populations has been successful at further separating some of the most promising Artemia populations of potential aquaculture use.Further, cysts from Tayrona show the smallest size, followed by Galerazamba, Kangarú, Manaure, Salina Cero and Pozos Colorados. Galerazamba has the thinnest chorion, followed by Tayrona, Salina Cero, Manaure, Pozos Colorados and Kangarú. Additionally, nauplii from Galerazamba present a small size followed by Manaure, Salina Cero, Pozos Colorados and Tayrona. The determination of FAME from Manaure, Galerazamba, Salina Cero and Tayrona, suggested high EPAs but low DHAs. Hence, all four populations sampled are not considered suitable for marine aquaculture unless fortified with DHA rich emulsions, according to actual aquaculture quality standards. The cyst quality study, conducted on cysts batches, shows that cyst collection and processing techniques need to be improved in order for them to be suitable for the growing Colombian aquaculture industry.The outcome of the population distribution study, shows Manaure, Galerazamba and Salina Cero as having a stable mean population distribution with a balanced adult (38%, 36% and 19%, respectively) to juvenile+nauplius proportion (62%, 64% and 81%, respectively), as well as a stable female:male sex ratio (1:0.84, 1:0.88 and 1:0.84, respectively). In contrast, Tayrona exhibits an unstable population distribution with a high proportion of adults (82%) and low juvenile+nauplius (18%) and female:male ratio (0.88:1), thus recruitment of the juvenile and nauplius cohort to assure continuity of the species in this biotope is below sustainable levels. The results for the reproductive experiments (mean cyst production per female) do not entirely agree with the estimated cyst production potential at each site (field work results).These results difference is likely to be due to the interaction in the field among the three parameters (salinity, percent O2 saturation, and nitrate) on cyst production, particularly in the case of Salina Cero. Similarly, nitrate levels might have been affected by salinity. The latter may be supported, in part, by the observation of low nitrate levels during the peak of cyst production during this study. The genetic study on some Caribbean Artemia franciscana strains based on RAPDs generated two similar dendrograms with the same separation for the two Caribbean population clusters (middle Caribbean: Pozos Colorados, Tayrona, Manaure, Venezuela-PAV, Bonaire and Curaçao and lower Caribbean: Galerazamba and Salina Cero). Moreover, the clustering pattern obtained suggests that the populations in these two clusters are not genetically identical.Further, the splitting of the Artemia populations coincides with the existence of a geographical barrier in Colombia named the Sierra Nevada de Santa Marta. The Sierra Nevada might constitute a geographic barrier to shorebirds and hence Artemia cyst dispersal further south. The discriminant analysis based on morphometric characters, assigns male and female individuals into their proper population group (North American and Caribbean coast) to which they belong by only one discriminant function (100% confidence). However, male morphometric characters separate better population groups than the female characters, since all Colombian populations are correctly clustered in the Caribbean coast whereas the SFB population fall into the North American group, with no overlapping between both, as it happens with females.Similarly, for Artemia populations classified by their geographic origin, male and female individuals again separate the Colombian populations from the North American (SFB) populations. According to the analysis, Salina Cero male population is similar to its neighboring Galerazamba population and is also related to the other Colombian populations, and this is consistent with the previous findings using RAPDs and also likely to be explained by the existence of a geographic barrier (Sierra Nevada de Santa Marta). Apparently, as deduced from the influence of lunar cycles and sampling time study the conglomerates formed by brine shrimp are asynchronous. Finally, it is recommended to conduct Artemia surveys preferably late in the evening or alternatively during early morning since Artemia tends to distribute more uniformly during the evening (dark and cool), when water temperature is lower, particularly in saltworks, where the evaporation basins are shallow.

Desde la fantasía y la magia de la creación indígena hasta la derrota del conquistador como resultado de la ambición y la destrucción, son algunos de los elementos que se combinan para ofrecer un nuevo comienzo a lo que hoy se llama Cultura Latinoamericana. Con el juego de formas, colores y sonido se produce un pieza en la que se busca el regreso a una identidad propia.Principales objetivos:Presentar tres escenarios de la civilización latinoamericana a través del uso de símbolos precolombinos, elementos históricos, el formato de cuento y la animación como medio de crítica política y social en contra de la discriminación cultural en Norte América.Entender el concepto de cultura como un evento cíclico de tesis, antitesis y síntesis.Crear una interpretación personal sobre lo que es la cultura en Latino América.Comentario Técnico: Tres historias para la creación es una producción bi y tridimensional que utiliza los programas de animación Maya y After effects como fuente principal para generar imágenes en continua transformación explorando el uso de máscaras de vectores y cámaras múltiples en el mismo cuadro. También explora el juego con el área de encuadre como un elemento variable que forma parte de la historia.Programas utilizados:Alias Wavefront Maya 3.0Sensable Technologies Freeform 4.0Adobe Photoshop 6.0Adobe After effects 5.0Final Cut Pro 2.0Sound Edit 16 2.0Adobe Ilustrator 10.0Fractal Painter 6.0

Green technology developments bring public managers to the table with entrepreneurs who want to promote new technologies and share regard for the public good. The introduction of green technologies to the general public evidences that the challenge of technological change spans to a sphere of social interactions that operate in the breakthrough. This phase is best characterized as an inter-organizational process and my research explores the patterns that emerge through it. My research focuses on the development of a solar energy venture, the Solar-to-market initiative based in Massachusetts. By treating the creation of this venture as a dynamic system, I will highlight the role of public-private and third sector partnerships in shaping policies and technology innovation. The core question of the research is addressed by mapping out the networks that emerge throughout the process from project design to implementation.I urge public managers and entrepreneurs to consider the following aspects when managing green technological environmental ventures: (1) Design a framework for setting goals, policies, responsibilities and negotiation terms during the technological development and implementation phase, from design to commercialization. (2) Because of the complexity involved in green technological innovation, organizations demand a high degree of interdependence to share knowledge, complementary operational capabilities and joint action; thus creating the mechanisms to maintain these interactions is crucial. (3) A shift from traditional energy systems requires a change of social structures and institutional settings that demand the participation of the various stakeholders to co-produce and adopt the technological developments.(4) The societal change that technology demands, can be reached by mobilizing civic groups and social structures without threatening public institutions. (5) Green technological environmental ventures can be managed through an experimental and learning-oriented approach that enables a strategic niche management. Learning from small systems provides basis for policy innovations that are necessary for paving the way to sustainability as practices, such as energy consumption demand not incremental changes but a system transformation. In brief, I consider that a system of adaptive technology developments based on smaller operating parts within larger systems, which have acquired valuable knowledge and experience while working cooperatively, can contribute to a more equal and sustainable development.

This thesis develops arguments relevant to scientific writing, the understanding of genres in scientific writing, and the construction of scientific fields. It is concerned with how review articles construct the fields of study which they describe. Using constructivist and relativist perspectives from the sociology of scientific knowledge, the research is based on a textual or discourse analysis, emphasizing the contingency of collective phenomena, such as scientific fields. In the first part, the co-formation of the genres of research and review writing is addressed; the focus is on how review writing has been portrayed by historians and rhetorical analysts, bibliographers and information analysts, compilers of guidelines on scientific writing and by scientists, editors, and reviewers.Other central questions include who is expected or authorized to write reviews, as well as to what extent reviews are considered to be a discrete genre in the production of scientific knowledge; it is argued that in practical circumstances (i.e., when classifying research articles and reviews, producing guidelines on reviewing, or awarding scientific reviewing) the straightforward differentiation of two distinct forms of writing becomes blurry. In the second part, the construction of the field of Darwin Studies is examined, through the analysis of various reviews proclaiming the constitution of the field and aiming to put it in order.This ordering is produced through the establishing of boundaries with other fields; mapping it in a comprehensive manner, that is, providing criteria of inclusion and exclusion; building a biography for the field, thus identifying its origins and development through time; and through defining the “state of the art”, which includes introducing its central figures, research problems, and ongoing controversies. The production of each construction of the field as an inter-subjective definition of a given entity, and not as a prejudiced or idiosyncratic representation, requires the careful management of the identity, authority, and credibility of the reviewer. The successful negotiation of a relatively stable constitution of a field is produced through inter-textual reiteration and reinterpretation.

The purpose of this report is to investigate the performance, measured in terms of Key Performance Indicators (KPIs) of a UMTS radio network (UTRAN) under different traffic and mobility scenarios and develop general guidelines for dimensioning the UMTS network optimally. In this work, simulations are performed using Wines tool, which is a dynamic simulator that models all the radio-resource management functionality of the UTRAN. Two main series of experiments have been performed. In the first series, the distribution of the traffic is homogeneous and the main purpose is to find capacity figures when increasing the traffic density of one of the four possible defined services (WWW, FTP, voice and video-call) and also with a given traffic mix involving all services together.Two mobility profiles are used (pedestrian and vehicular). In the second series of experiments, a more realistic scenario, based on detailed geographical characteristics relevant for signal propagation, and traffic densities based on traffic maps (non homogeneous scenario), has been simulated. The purpose was to analyze the possible differences in capacity between the “ideal” model and the more “realistic” model.For the single-service scenario analysis, circuit-switched services (speech and video-call), it can be observed that the capacity is mainly uplink-limited. The corresponding results for the packet-switched services (FTP, WEB) have shown that capacity is mostly downlink-limited, as it was expected due to the more asymmetrical data rates in the downlink compared to the uplink for both services. For the service mix analysis in both scenarios (homogeneous and non homogeneous) it was found that the capacity is mostly downlink-limited (i.e. the downlink power target level is exceeded before the uplink load target level).

Después de más de 20 años de éxito del sistema indexado de financiamiento de vivienda (UPAC) a través del cual la vivienda se convirtió en un sector líder como parte de una amplia estrategia de desarrollo diseñada para acelerar la urbanización e industrialización colombiana, el sistema sufrió modificaciones estructurales en donde pasó de estar únicamente atado a la inflación para pasar a indexarse a la tasa de interés también.Esto generó una fuerte alza en el costo real del financiamiento, desencadenando una crisis de pagos por parte de una alta proporción de usuarios que terminaron perdiendo su vivienda y desatando una crisis social. Esta situación paralizó el sector de la construcción, retrocediendo fuertemente en el proceso de crecimiento a través de este modelo.El gobierno intentó reparar el modelo volviendo al esquema original (atado únicamente a la inflación) y renovando el nombre del sistema con la iniciativa UVR. No obstante, este sistema no ha podido recuperar la capacidad motora que tuvo en sus comienzos.

The main Topic of this dissertation is to critically analyze the obligations of States’ parties to the TRIPS Agreement in relation to the extent of protection that they are bound to confer on first and second medical use patents. In this sense, the Viagra case illustrates the tensions between the national pharmaceutical industries of the States members of the Andean Community and a leading pharmaceutical company like Pfizer. The dissertation pretends to demonstrate that the decisions taken by the authorities in the Andean Region were consistent with the international minimum standards of IPRs as embodied in the TRIPS Agreement.The Viagra case is the most important series of administrative and judicial decisions concerning first and second use patents in the Andean region. It is composed of the administrative rulings of the member States national authorities of the Andean Community, by the administrative rulings of the Andean Community Secretariat and by the judicial decisions of the Andean Tribunal of Justice. This case was elected as the topic of the dissertation because it doesn’t follow the international trend to expand the levels of patent protection, which has occurred in two ways. First, the scope of patentable subject- matter has been given an inclusive interpretation. Secondly, the restrictions on patentability have been narrowly interpreted.

En este trabajo se presenta un estudio sobre la soldadura y caracterización de uniones de ductos de acero API 5L-X80 con diferentes alambres tubulares. Tales procesos son evaluados bajo la influencia de la temperatura de precalentamiento mientras el aporte de calor de la soldadura es mantenido constante. Las soldaduras fueron realizadas en la posición plana 1G, con la pistola fija y el ducto girando. Se soldaron tubos de 762 mm de diámetro externo y 16 mm de espesor.Fueron utilizados alambres con propiedades mecánicas diferentes de las del metal base, usándose en la condición undermatched. El proceso de soldadura por arco eléctrico con alambre tubular fue usado en dos variantes, autoprotegido (FCAW-S) y con protección auxiliar de gas (FCAW-G), cada uno de ellos aplicados por medio de seis pases sobre una unión de tope y bisel en “V”, con la utilización de tres niveles de temperatura de precalentamiento (ambiente, 100 y 160 °C). Estas temperaturas fueron mantenidas entre pases.La caracterización de las uniones es presentada en función de los ensayos mecanicos realizados: resistencia a la tracción, dureza y tenacidad. Para la ejecución de estos ensayos se tomó como referencia las normas API 1104, AWS y ASTM. Como criterios de aceptación fueron utilizadas las normas API 1104 y API 5L. A partir de los resultados obtenidos fue posible observar que es viable la soldadura de ductos API 5L-X80 con este tipo de alambres tubulares, cumpliendo con los requisitos de las normas de referencia, sin ser necesario el uso de temperatura de precalentamiento.

Miguel Angel Rojas es uno de los artistas colombianos contemporáneos más prolíficos. Sus inicios como dibujante hiperrealista, su incursión en la pintura neoexpresionista de la siguiente década, sus obras indigenistas – interculturales de los años 90 y sus más recientes obras políticas referidas al narcotráfico son en conjunto, manifestaciones de un espíritu creativo, curioso y autoexigente.Sin embargo su obra fue poco conocida y divulgada hasta fechas recientes. Su actitud estética, profusa, ecléctica y abierta a los cambios, refleja el temperamento del mejor arte colombiano, aquel que le ha permitido entrar y salir con éxito y desprejuicidamente de las impredecibles y siempre cambiantes corrientes y contracorrientes del arte contemporáneo sin perder de vista su realidad local.Esta investigación intenta realizar por primera vez una revisión de la obra total del artista, cubriendo tres décadas de trabajo. Se da a conocer su obra y la interesante producción colombiana actual.