Improving the organization of fruit and vegetable production-assembly systems in the coffee zone of Colombia, a case study in the La Mesa región.

Doctor of PhilosophyDoctorad

Kukama Radio: the Politics and Aesthetics of Indigenous Media in Peruvian Amazonia

This dissertation is about the political and aesthetic dimensions of Indigenous media in Peruvian Amazonia. It explores how Kukama media-makers use aesthetic mastery to engage in three key political fields in Amazonia: indigeneity, historicity, and environmentalism. I specifically examine the audiovisual discourses and media-making practices coming from an Indigenous radio station called Radio Ucamara, located in the town of Nauta in Northeastern Peru (Loreto region). Drawing on place-based ethnography and digital research methods, I analyze the way this radio station instrumentalizes multiple digital and non-digital media forms to make visible (and also audible) their identities, violent histories, and cosmological worlds amidst their confrontation with the Peruvian neoliberal state and oil companies. The dissertation also contemplates how through these processes of mediatization, Amazonian ontologies, mytho-histories, and identities are being reimagined. For this purpose, I focus both on the analysis of media products (e.g., music videos, documentaries, journalistic reportage, murals, books) and the social dynamics surrounding those creations, to understand the way Kukama media producers take part in ongoing struggles for the revitalization of the Kukama language, seeking justice for the rubber times violence, and stopping the pollution of Amazonian rivers. Following theoretical frameworks derived from the anthropology of media and the anthropology of music and verbal art in Lowland South America, I argue that media aesthetics is becoming a major instrument in building political power in the region

Investigation of pathophysiologic trends in Caucasian and Afro-American hypertensives by means of heart rate variability recording during upright tilt-table testing

The incidence of hypertension is more prevalent among the Afro-American population than the Caucasians and there is not a satisfactory explanation for this discrepancy. Heart Rate Variability (HRV) has been demonstrated to reflect the relative activities of the sympathetic (SMP) and parasympathetic (PSMP) divisions of the autonomic nervous system (ANS). This study consisted in comparing the HRV, as well as the blood pressure (BP) of four different groups during up-right tilt table testing. The subjects were grouped by age, gender, race and health condition. Analysis in time and frequency domain was applied to the data. In the frequency domain, the LF and HF bands were studied. In the time domain, a new parameter was proposed to analyze the data. As a result, the ratio of the FIF area, from the supine to the standing positions, was higher in the hypertensive group than the normotensive one, and the ratio of the LF area was higher in the normotensives than the others. On the other hand, Afro-Americans had a higher LF area ratio than Caucasians and a lower HF area ratio

A Continuous Mathematical Model of the One-Dimensional Sedimentation Process of Flocculated Sediment Particles

A new continuous one-dimensional sedimentation model incorporating a new continuous flocculation model that considers aggregation and fragmentation processes was derived and tested. Additionally, a new procedure to model sediment particle size distribution (PSD) was derived. Basic to this development were three different parametric models: Jaky, Fredlund and the Gamma probability distribution (GPD) were chosen to fit three different glass micro-spheres PSDs having average particle sizes of 7, 25 and 35 microns. The GPD provided the best fit with the least parameters. The bimodal GPD was used to fit ten sediment samples with excellent results (\u3c 5% average error). A continuous flocculation model was derived using the method of moments for solving the continuous Smoluchowski coagulation equation with fragmentation. The initial sediment PSD was modeled using a bimodal GPD. This new flocculation model resulted in a new general moments’ equation that considers aggregation and fragmentation processes, which is represented by a system of ordinary differential equations. The model was calibrated using a genetic algorithm with initial and flocculated PSDs of four sediment samples and four anionic polyacrylamides flocculants. The results show excellent correlation between predicted and observed values (R2 \u3e 0.9878). A new continuous one-dimensional sedimentation model that resulted in a scalar hyperbolic conservation law was derived from the well-known Kynch kinematic sedimentation model. The model was calibrated using column tests results with glass micro-spheres particles. Two different glass microspheres particle size distributions (PSDs) were used with average diameters of 7 and 37 microns. Excellent values of coefficient of determination (R2 \u3e 0.89, except for one test replicate) were obtained for both the small and large glass micro-spheres PSDs. These results suggest that the proposed sedimentation model can be expanded to model the sedimentation process inside a sediment pond