In many cultures palms offer a vast number of products, especially Non-Timber-Forest Products (NTFPs), which have been traditionally used by indigenous and mestizo groups in Latin America. Some species have gone beyond the domestic use and their commercialization has reached local, national and international markets. Among the palm products that are widely commercialized in South America are palm heart (Euterpe oleracea), extracted from the young unfolded spear leaves of the palms, and the handicraft woven from fibers (Astrocaryum chambira, A. malybo and A. standleyanum), all extracted from the leaflets. In Colombia, these four palm species are economically important for the harvesting communities as well as for wholesalers and retailers.However, commercialization has been based on the extraction of raw material from wild palm stands up to the point that several palm species are threatened by developing markets for their products, and the need of income for the harvest communities and industry. The general objective of this thesis is to describe the value chains of palm products from E. oleracea, A. chambira, A. malybo and A. standleyanum in different Colombian regional markets, as well as national and international markets, and to analyze the economic importance, potentials and implications of this trade.Data on the four value chains was gathered through interviewing all actors of the value chain and revising the literature about the commercialization of these palm products. This study assesses the main actors or organizations in the commercialization chains, their specific activities, different routes to trade products, and how well the chains currently work by conducting a qualitative and quantitative value chain analysis.Major results involve particular dynamics and distributions of the profits along each value chain, as well as common aspects: the value chains are short, simple, the commercialization channels need to be strengthened, the scarcity of the raw material is a crucial constraint for the commercialization of the products.Unsustainable harvest practices are common. Moreover, the marketing potential of each group of palm products as well as promised target markets are characterized. The principal contribution of this thesis consists in shedding light on the current status of the value chains of these four palm species in Colombia, and proposing possible routes of development to strive for sustainability in each of the value chains analysed. Moreover, this study provides information about the economic importance of the palm products to the local communities and the need to upgrade the commercialization channels, products and communal incentives to assign equitable incomes along the chain.

In earlier decades, a number of authors have been looking at how commuters value the usefulness of travel time and at which point it is still considered to be a disutility to minimize. This document presents the results of a survey which was carried out on different transportation modes in Northern California. The results of this study show how the utility of travel time may change from one person to another, unveiling the latent relationship between several factors (i.e. Attitudinal factors, primary mode of transportation, age, gender, etc.) and what we consider the usefulness of travel time. This study included several considerations made from different approaches, including linear regression analysis and ordered probit models.The dependent variable was always considered to be the usefulness of travel time represented in the final survey by an ordinal variable. Moreover, the study comprised data segmentation (i.e. primary mode of transportation) which explained some conceptual differences between a pooled model and “active-passive” models. Finally, the outcome of this study shows how active travel modes (i.e. Car driving) are usually the most unattractive, for the reason that the possibility of engaging in different activities while traveling is very limited. Similarly, how the activity itself may change the perception of travel from a disutility to minimize to a transition or mostly useful time.

The focus of this study is to build, from the “bottom-up”, a market with artificially intelligent adaptative agents based on the institutional arrangement –monetary policy, regulations, trading conventions– of the Colombian Foreign Exchange Market prevailing between December 1994 and September 1999 in order to determine simple agents´ design, rules and interactions that are sufficient to create interesting behaviours at the macroscopic level – emerging patterns that replicate the properties of the time series from the case study. Tomado del resumen de este documento

En esta tesis se aborda el problema de cuánto pescar maximizando el beneficio y disminuyendo el riesgo de colapso mediante una aproximación matemática a tres stocks diferentes, la anchoa en el mar de Alborán, la anchoa en el golfo de Cádiz y la merluza del Atlántico Norte. Teniendo en cuenta las condiciones y particularidades de cada stock, el enfoque para los tres ha sido diferente. Para la anchoa del golfo de Cádiz y del mar de Alborán, aunque se ha utilizado principalmente la interacción entre el medio y el ciclo de vida de la especie, los tipos de forzamiento ambiental y su relación con el ciclo vital son diferentes. Sin embargo, para la merluza se ha tenido en cuenta la relación entre la pesca y su biología, que no se conoce totalmente, ya que el efecto del medio ambiente es menos representativo. En el golfo de Cádiz, ya se conoce la dinámica del forzamiento ambiental causada principalmente por la temperatura, los fuertes vientos y las descargas del río Guadalquivir, y por lo tanto se procede directamente a modelar dichas interacciones con un modelo de doble resolución temporal: Una resolución semanal para las primeras etapas vitales, y mensual para juveniles y adultos. Este modelo logra mejorar estimaciones previas de juveniles y provee estimaciones coherentes de la distribución mensual por tallas de la población mostrando que la doble resolución incorpora adecuadamente la variabilidad del tamaño de la población causada por la influencia del medio ambiente en las etapas tempranas y la dinámica de crecimiento. En el mar de Alborán era necesario analizar primero los factores que podrían estar causando el forzamiento y una indagación exhaustiva logró revelar una conexión entre su sistema circulatorio y el nivel de capturas, donde se ve claramente que el usual alto nivel de energía del sistema circulatorio de la zona no es favorable para el reclutamiento, y que cuando este colapsa es posible la existencia de reclutamientos excepcionales de esta especie. No obstante, la herramienta estadístico-matemática que está presente en todos es el análisis bayesiano que permitió la incorporación de elementos complejos, desde el forzamiento ambiental a la dinámica de capturas y descartes con diferentes flotas, cuantificando la incertidumbre subyacente en todos los procesos involucrados. Las técnicas bayesianas proveen en este trabajo una gran herramienta para asesorar pesquerías con una aproximación más realista a la dinámica biológica y ecológica de las poblaciones. Además, el conocimiento derivado de la aplicación de dichas técnicas se puede proyectar sobre elementos socioeconómicos, diseñando herramientas de gestión que tengan en cuenta el impacto del ecosistema y evaluando su funcionamiento. Por este motivo fue posible proponer en el caso del golfo de Cádiz, una herramienta de evaluación de diversas estrategias para la gestión del recurso, resaltando la importancia de aquellas que tienen en cuenta la interacción entre el ecosistema y la biología de la especie estudiada. La herramienta se basa en la aplicación de un esquema de seguros que permite calcular el valor de la información ambiental aplicada a la gestión, usando conceptos como ingreso medio, prima y riesgo de colapso. Los resultados de una estrategia propuesta que incluye el forzamiento ambiental muestran que el riesgo económico no se disminuye, dado que la volatilidad del ingreso y el valor de la prima son mayores, pero si disminuye el riesgo de colapso y se genera un monto de ingresos tal que permite compensar dicha volatilidad. El aumento considerable de ingresos obtenidos bajo esta estrategia hacen que esta herramienta sugiera la posibilidad de estabilizar ingresos sobre un recurso inherentemente fluctuante. Por tanto, representa un precedente para la posibilidad de un manejo cooperativo del riesgo que responda a una cuota variable determinada por el medio ambiente. A pesar de las múltiples ventajas de las técnicas bayesianas aplicadas tanto al modelado del ecosistema y sus interacciones con la pesca, como a la gestión del recurso, el tiempo computacional es demasiado elevado para modelos con un gran número de parámetros y procesos como el de la merluza. El rápido avance tecnológico resolverá este inconveniente y hará que esto sea posible en el futuro, permitiendo que la medida de incertidumbre que provee esta herramienta pueda ser la base de la toma de decisiones relevantes para el sector pesquero. Resumen completo tomado de esta tesis.

Este archivo contiene el resumen de la tesis; la “Introducción general”; los objetivos generales y específicos, diferenciados por capítulos, y el capítulo 1. En tal capítulo se desarrolla un nuevo modelo bayesiano para la anchoa en el golfo de Cádiz. Dicho modelo forma parte de esta tesis y fue aceptado para su publicación en el Canadian Journal of Fisheries and Aquatic Sciences. Es un modelo con resolución temporal semanal para las primeras etapas vitales, y mensual para juveniles y adultos que incorpora la influencia del medio ambiente para etapas tempranas y una estructura de crecimiento que permite estimar la distribución mensual de tallas. Este modelo, además, provee una distribución mensual de las capturas a partir de los parámetros estimados, lo que permite simular series temporales y comparar como se comportarían las capturas usando diferentes estrategias de pesca para diseñar una que sea óptima. Texto tomado y adaptado de la “Introducción general” de esta tesis.

En este capítulo se muestran claros indicios de que la disminución en la fuerza del chorro atlántico (corriente de agua con dirección Este, pasando por el Estrecho de Gibraltar) permite una mayor supervivencia de la anchoa en el mar de Alborán, en sus estadios más tempranos, aumentando así las probabilidades de un reclutamiento exitoso y, en consecuencia, un alto número de capturas. Texto tomado y adaptado de la “Introducción general” de esta tesis.

Abstract: Greater local economic activity could improve children’s educational attainment by expanding the resources that could be invested in education. However, increased economic activity could also result in limited educational gains, as children may be induced into employment. This paper studies violence as an alternative explanation for the limited gains, focusing on Colombia, an oil-producing country with a long-standing civil conflict. Existing evidence shows that oil price shocks fuel civil conflicts; I explore whether increased violence undermines any positive effect greater oil resources might have on educational attainment by considering exogenous increases in international oil prices and geographic variations in oil production. Estimates suggest rising oil prices between 1998 and 2005 had limited effects on the number of years of schooling and whether children are behind grade for their age. Moreover, oil price shocks had small but surprising negative effects on primary school enrollment. My analysis reveals that the negative effects on younger children education might be driven by the aforementioned increase in civil conflicts and by additional oil resources being invested in sectors other than education. Resumen: Una economía más dinámica puede mejorar la escolaridad de los niños, a través de los mayores recursos que se inviertan en educación. Sin embargo, un mayor dinamismo también podría resultar en pocas ganancias educativas, si incentiva el trabajo infantil. El presente artículo explora la violencia como una explicación alterna a este fenómeno, enfocándose en Colombia, un país productor de petróleo que ha sufrido de un largo conflicto armado. Con base en evidencia existente que documenta la intensificación del conflicto armado causado por los aumentos en los precios del petróleo, éste artículo investiga si la mayor violencia destruye el efecto positivo de los mayores recursos petroleros en la escolaridad de los niños. Este artículo utiliza el aumento exógeno en los precios del petróleo y la variación geográfica en la producción de petróleo para identificar dicho efecto. Los resultados sugieren que el aumento en los precios del petróleo de 1998 a 2005 no tuvo ningún efecto en los años de escolaridad de los niños, ni en su probabilidad de estar atrasados en el colegio. Más aún, los aumentos en los precios del petróleo tuvieron efectos pequeños pero negativos en la matricula primaria. El análisis sugiere que éstos efectos negativos pueden darse debido a la intensificación del conflicto armado y a la inversión de los recursos petroleros en sectores diferentes a la educación.

Documento de análisis en el que se estudia la forma en que el cristianismo se ha permeado por distintas doctrinas o religiones, y se modifica en función de los intereses de los fieles. Asimismo, se sostiene que las creencias del cristianismo no pretenden ofender a aquellos que tienen otro tipo de creencias diferente a las que ésta religión plantea.

Current research on automated vehicles focuses mainly on the drivers of automated vehicles, on its potential to improve the efficiency of traffic operations, safety, congestion and societal benefits, public’s acceptance of automated vehicles as a transport system and the willingness to buy automated vehicles. Nevertheless, there is a research gap in an equally important topic of research; the interactions of the automated vehicles with Vulnerable Road Users (VRU), i.e., cyclists and pedestrians. The WEpods (shuttle buses) are the first automated pods on public roads amidst other traffic, for an extended period of time in the province of Gelderland, in the Netherlands. The main research question revolves around the safety perception of vulnerable road users (VRUs) when interacting with automated vehicles, specifically at unsignalised intersections, and their crossing behaviour in comparison with traditional motor vehicles. The data on road users’ perception was gathered through face-to-face interviews (𝑁=22), a focus group (𝑁=8), and an online survey (𝑁=198). The results of this research showed that in terms of perceived safety, in general, VRUs (pedestrians and cyclists) feel significantly safer when sharing the road with the WEpods (max. speed of 15 𝑘𝑚/ℎ) compared to traditional motor vehicles (max. speed of 30 𝑘𝑚/ℎ). However, cyclists reported feeling less safe when interacting at unsignalised intersections with the automated vehicles, while there was not significant effect on pedestrians. Similarly, pedestrians more often opted for crossing facilities in the presence of the WEpods than in the presence of traditional motor vehicles (this can be interpreted as the result of perhaps feeling less safe), while no significant difference was reported for cyclists. Some of the reasons that could explain the trust in the WEpods are its low operational speed and the trust of most (81.1%) of the VRUs in the automated technology. This makes them expect the WEpods will stop in all possible instances, even when other traffic participants violate traffic rules. Surprisingly, a significant proportion (63.2%) of the participants was not aware of the presence of the steward on board of the WEpods. On the other hand, variables such as the awareness of the steward and having interacted with the WEpods increased the perceived safety amongst VRUs. Moreover, eye contact and gestures use as part of the actual interaction with human drivers of traditional motor vehicles particularly when crossing, was reported to be of importance by the respondents and has also been previously reported in the literature. The VRUs who said that they rely on cues given by drivers, more often indicated a preference to cross at dedicated facilities in the presence of the WEpods than those who stated not to depend on this type of communication. In order to substitute this lack of “real” interaction, information about the WEpods’ operations appeared to be desired by most of the participants in the form of visual information or a mix of auditory and visual. Finally, it was found that individual characteristics of the VRUs, such as their gender and other demographic variables could also have an impact on their perceived safety of VRUs interacting with the WEpods. The findings of the current research appear to point at a prudent attitude of cyclists and pedestrians in their interaction with automated vehicles. Nevertheless, this conservative mindset could be balanced by informing other road users about both, the features (e.g., the presence of a steward on board) and the limitations (e.g., the technology unable to respond to unexpected conditions) of the WEpods. It is considered that this information, along with a suitable communication of intentions of the vehicle to its surroundings are adequate tools to achieve a safe interaction between VRUs and automated vehicles.

Generally studies about identity and consumption have assumed that individuals are immersed in a context of abundance, in which their possibilities to fulfil their needs and desires to purposefully construct a consumption lifestyle are granted. Within this context, studies from the Consumer Culture Theory perspective have described how individuals navigate consumer culture by developing enduring relationships with possessions that help them to build identities and a sense of self. However, this is not always possible during every individual’s life. Certain situational factors not only provoke the individual’s loss of what they have already built, but also lead them to a restricted consumption context. The present study focuses on forced and uncertain changing events, those whose severity and/or rapid change disrupts an individual’s entire life. Through a phenomenological approach of the homeless experience, this study attempts to understand individuals’ transition into a restricted consumption context. The empirical data obtained from a twenty two month ethnographic study evidences that experiencing homelessness, individuals’ loss of possessions and the perceived uncertainty that characterizes life on the streets, trigger not only a self-transformation process, but also alter their relationship with the material world. The findings are contrasted with the current literature extending previous work about transition and consumption by: a) Proposing a new transformational routine to describe the forced self-transformations and how consumption (or the lack of it) becomes an element that influences the deconstruction and construction of a new self. b) Identifying how in a restricted consumption context, individuals develop a different relationship with the material world, and how this changes their modes of consumption.