O presente trabalho explora eventos de articulação entre coletivos indígenas da Serra Nevada de Santa Marta, localizada ao norte da Colômbia, e o estado, entendo-os como mundos com planos ontológicos e sistemas epistemológicos diferentes que coexistem e se reorganizam em cada um dos eventos, respondendo a hegemonias específicas em contextos particulares. A lei de Sé, ou lei da origem, estabelece uma política de alteridade que permite a existência de multiplicidades e diferenças que não se reduzem a princípios determinados, pois se trata de domínios móveis de conhecimento e pensamento que constroem pessoas, corpos e o território a partir de conexões parciais, potencialmente perigosas se não forem mediadas por lideranças espirituais (os mamos) para que aconteçam em harmonia e acordo entre os seres (Yuluka). As entidades múltiplas são subordinadas e ignoradas nos espaços de tomada de decisões sob o território, a partir de sistemas de conhecimento e políticas que entendem a natureza como cenário externo e objetivo, e a cultura como marcador da diferença que essencializa, isola e nega conflitos históricos e políticos, em um marco em que tanto natureza e cultura são potencialmente mercantilizáveis. Neste contexto, as práticas de patrimônio são uma estratégia do estado para regular a mercantilização da diferença, enquanto que os indígenas as apropriam como estratégia para defender a vitalidade do seu território, entendido como tecido de relações entre seres diversos. No entanto, a subordinação não implica a captura, pois as multiplicidades continuam coexistindo no movimento contínuo entre resistência e novos ou renovados mecanismos de captura. / Este trabajo explora eventos de articulación entre los colectivos indígenas de la Sierra Nevada de Santa Marta, ubicada al norte de Colombia, y el estado, entendiendo que se trata de mundos con planos ontológicos y sistemas epistemológicos diferentes, que coexisten y se reorganizan en cada uno de esos eventos respondiendo a hegemonías específicas, en contextos históricos particulares. La ley de Sé, o ley de origen establece una política de la alteridad, que permite la existencia de multiplicidades y diferencias, que no se reducen a principios predeterminados sino que se trata de dominios móviles de conocimiento y pensamiento que construyen personas, cuerpos y territorio a partir de conexiones parciales, que potencialmente pueden ser peligrosas si no son mediadas por los mamos para que se den en armonía y acuerdo entre los seres (yuluka). Estas existencias múltiples, son subordinadas e ignoradas en los espacios de toma de decisiones sobre el territorio, a partir de sistemas de conocimiento y políticas que entienden la naturaleza como un escenario externo y objetivo, y la cultura como marcador de diferencia que esencializa, aísla y niega conflictos históricos y políticos, en un marco en el que tanto naturaleza y cultura son potencialmente mercadeables. En este contexto, las prácticas de patrimonio son una estrategia del estado para regular la mercantilización de la diferencia, mientras que los indígenas la apropian como estrategia para defender la vitalidad de su territorio, entendido como tejido de relaciones entre seres diversos. Sin embargo la subordinación no implica la captura, pues las multiplicidades siguen coexistiendo, en el movimiento continuo entre resistencia y nuevos o renovados mecanismos de captura.

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In California's northern Sierra Nevada mountains, the fire-dependent processes of forest ecosystems have been interrupted and altered by human land use and fire suppression. U.S. Forest Service policy directs land managers to plan for a future that includes multiple use and the restoration of resilient ecosystems. Planning decisions are to be informed by an analysis of the range of variability of ecological processes at multiple scales. Current climate trends in the northern Sierra are of increasing temperatures, increased precipitation, and earlier snowmelt, as well as changes to the frequency and duration of drought. These climate changes have and continue to influence fire frequency, extent, and severity. For this thesis, project partners and I adapted the Rocky Mountain Landscape Simulator (RMLands), a spatially explicit, stochastic, landscape disturbance and succession model, for use in the Sierra Nevada. RMLands was used to simulate wildfires and vegetation dynamics on a portion of the Tahoe National Forest in California, first under historical climate settings and then under alternative climate trajectories based on the Representative Concentration Pathway RCP8.5 projections. I then quantified the historical and the future ranges of variability in the disturbance regime, seral stage distribution, and patch configuration, and compared these to the current landscape. My results suggest more frequent and extensive high severity fire, as well as higher canopy closure, than most other studies of mixed conifer Sierran forests. However, the results typically agree qualitatively with other research, and some differences may be due to differences in study design. Under warmer and drier future climate scenarios, the total area burned, and the proportion burned at high severity, increased. Due to fire's effects on vegetation, the current landscape departs from either historical or future conditions by several statistical measures. Based on these findings, I recommend that managers implement aggressive restoration efforts, utilize mitigation measures where the consequences of changing fire regimes are socially unacceptable, and carefully balance the needs of different ecosystems and of the resident communities. My study can be used to inform goals and specific strategies in restoration planning and help project planners think about impacts at the landscape scale.

Low wind speed conditions should be studied because these conditions can present risk, particularly for areas immediately surrounding the release point, where high concentrations can occur and not dissipate. The following research attempts to clarify the processes governing both the general and low wind speed cases by determining the accuracy and uncertainty of standard prediction methods for contaminant plume transport in low wind speed plume modeling. Multiple techniques were utilized to incorporate field measured data, previously gathered for a different purpose, to generate parameter distributions and ground-truth data that could be used in stochastic models for chemical plume prediction. These data were taken during a multi-day experiment performed on Frenchman Flats, a flat, dry lakebed, at the Nevada Test Site (NTS) in February of 2007 and include weather data and chemical concentrations throughout the chemical release time. I organized these data into continuous time series for each sampling location, which were represented as vectors for the statistical and mathematical analysis. I then animated these vectors with respect to time and performed a stochastic analysis which I compared to these observed vectors. Predicted vectors of chemical concentrations, based on the statistical parameter distributions generated from the observed vectors were developed and a statistical analysis was performed on the results of the stochastic process to determine how well the model predicted the plume. It was found that stochastically modeling, with SCIPuff, of contaminant plume releases in low wind speed conditions is not accurate. This was expected because below 2 m/s, plumes no longer have a Gaussian distribution and are difficult to predict because of fluctuating winds. In fact, the model only accurately predicts the period before the plume arrives at the sensor when no plume is present. It is possible, and even probable, that stochastic modeling of contaminant plumes will provide a means to compute the bounds of a release, when coupled with a model that is accurate for low wind speed conditions and includes all the complexities of the wind field. An unexpected finding is the fact that the vertical dimension of wind movement cannot be ignored in low wind speed conditions. When planning future experiments, special attention should be paid to obtaining a good representation of the 3-D wind profile.

This thesis focuses on fisheries managers’ efforts to restore native cutthroats to northern Nevada’s Pyramid Lake for recreation, and the Paiutes’ battle to preserve them as a means of livelihood. Their efforts to reconstruct the fishery revealed the implausibility of environmental restoration, but more importantly underlined the motivations necessary to attempt it. Chapter 2 describes how the Pyramid Lake Lahontan cutthroat— historically an important subsistence resource for Northern Paiutes— were initially exploited for profit in the late 1800s and early 1900s, and gradually destroyed as agricultural interests diverted the Truckee River’s water and industrial pollution contaminated the trout’s aquatic habitat. Fisheries managers in Nevada turned to artificial propagation to meet the demands of fishermen and replace the native fish industrialization destroyed. The Nevada Fish and Game Commission experimented with non-native introductions and like most of the West became proponents of rainbow trout and their recreational potential. Chapter 3 narrates a history of the Nevada Fish and Game Commission’s project to restore trout to Pyramid Lake in the 1950s and 1960s after its native cutthroat became extinct in the early 1940s. For the Commission, restoring Pyramid Lake meant establishing trout and salmon populations— native or not— to feed the growing outdoor tourism industry. While the Commission made plans to restore natural spawning runs, these were unsuccessful, and the Commission relied on stocking the lake to maintain the fishery. However, these experiments failed and eventually cutthroats from other lakes in Nevada proved better occupants of the lake. Chapter 4 describes the native cutthroat’s role in the water debate carried out in government agencies and in the courts in the 1970s and 1980s to decide whether or not water diverted from the Truckee for agriculture should be returned to the Paiutes to support their shrinking lake and dwindling fishery. Environmentalist groups like the Sierra Club joined the Paiutes in their effort to gain water that would allow for the native fishery’s restoration. Their vision clashed with that of agriculturists who feared losing water they depended on for their crops. However, after a lengthy struggle, the Paiutes won an important victory toward preserving their lake.

One of the primary purposes of the investigation was to examine the impact of a number of variables on the incidence of low birth weight in two states, Utah and Nevada, that have divergent low birth weight incidences. The sample size obtained from birth certificate data for this purpose was 51,147 (1969-1974) for Nevada and 26,464 (1970) and 29,422 (1974) for Utah. Additionally, separate analyses were made for Utah and Nevada data available for the year 1974. The respective sample sizes for this year were 29,422 (Utah) and 8,256 (Nevada). Least squares analysis indicated sex of the infant, race of the mother, age of the mother, parity, and county of residence were al l significantly related ( P.O:: 0 . 01) to birth weight of the infant . Examination of the birth certificate data indicated, the unmarried, black adolescent is most apt to bear a low birth weight infant in both Utah and Nevada , but the incidence of young, black, unmarried adolescents is higher in Nevada accounting in part for the divergent overall incidence of l ow birth weight be tween the two states. To supplement birth certificate information, additional questionnaire sampling was conducted in Utah and Nevada. Information on pregravid weight, pregnancy weight gain, protein intake , energy intake, smoking habits, socio -economic status, exercise patterns and over-the -counter drug use was obtained from 184 women (Utah 88, Nevada= 96). Student's t-test, stepwise regress i on and least squares analysis indicated pregravid weight and pregnancy weight gain "ere the on l y variables significantly related (P 1!.. 0.01) to birth weight .

Through a myriad of practices, anthropogenic land and water use has caused the localized extirpation or complete elimination of many native fishes throughout North America. Specifically, native salmonids have seen substantial declines in population sizes and geographic distributions due to a number of factors, including habitat loss or degradation, overharvest, or the introduction of non-native competitors and predators. Among those affected, the 14 subspecies of cutthroat trout found across western North America have been subject to two extinctions and five listings as Threatened as per the Endangered Species Act. Lahontan cutthroat trout Oncorhynchus clarkii henshawi have experienced marked reductions throughout their native range in the western Great Basin, U.S. In Pyramid Lake, Nevada, where they were once locally extirpated due to overfishing, water loss, and degraded spawning habitat, Lahontan cutthroat trout have been successfully stocked and managed, though they do not routinely reach their pre-extirpation sizes. With little research to determine the factors influencing Lahontan cutthroat trout in Pyramid Lake, I used a suite of modeling tools and empirical data to elucidate the influence of the current surrounding environment on Lahontan cutthroat trout in Pyramid Lake. To identify important food web interactions that may affect the availability of food to Lahontan cutthroat trout, I used diet composition and stable isotope analyses of carbon and nitrogen to understand dietary trends. Large Lahontan cutthroat trout (>400 mm TL), along with non-native Sacramento perch Ambloplites interruptus, relied most heavily on fish prey, yet neither species showed signs of cannibalism or preying on the other species. Diet composition and stable isotope analyses also indicated that Lahontan cutthroat trout rely mostly on tui chub Gila bicolor and other fish for food. I also used results from bioenergetic and hydroacoustic analyses to compare the number of tui chub consumed by trout to the number of tui chub in the lake, during the time of this study. Results from these analyses suggest that trout consume well below the number of tui chub available in the lake, indicating that trout are not limited by the availability of tui chub. Lastly, I used a number of biotic and abiotic predictors to determine which factors influence the distribution, and subsequently abundance, of trout in Pyramid Lake and found that biotic factors were very weak predictors of trout distribution, further indicating that trout are not limited by food resources in Pyramid Lake.

Amino acid geochronology based on fossil molluscs provides a useful approach to determining the Quaternary history of Great Basin lakes. The Lahontan basin, Nevada, and the Chewaucan basin, Oregon, in the northwest corner of the Great Basin, both contained lakes during the Quaternary. The aim of this study is to improve the Quaternary geochronology in these two basins by measuring time-dependent changes in amino acids preserved in fossil molluscan shells. The abundance of D-alloisoleucine relative to Lisoleucine (All) characterizes the extent of racemization, which increases with age and Ul forms the basis of relative and correlated ages. An age-calibration curve for Vorticifex was developed using All ratios in shells from layers with radiocarbon-dated shells and with one thermoluminescence date in the Chewaucan basin. The All ratios from non-dated deposits were assigned ages from this calibration curve. The All ratios in 77 samples (-350 shells) of mainly Vorticifex were analyzed to improve the lake chronology in the Lahontan and Chewaucan basins. From the stratigraphic position, All ratios in the shells, and previously published radiometric ages, at least five and possibly six lake cycles were inferred in the Lahontan basin for the Quaternary period. Shells with highest All ratios ( -0.8) might correlate with the Rye Patch Alloformation, named for deep-lake sediments deposited in the Lahontan basin -630 ka. The next younger lake deposits are ascribed to the Eetza Alloformation. On the basis of the amino acid data, two and possibly three distinct lake expansions took place during the Eetza lacustrine episode, which lasted from -385 to 145 ka. Deposits of the Sehoo Alloformation ( -35 to 12 ka) can be differentiated from older deposits on the basis of All ratios in mollusc shells. Finally, a few shells with low All ratios near Pyramid Lake may indicate a minor lake expansion during the Holocene. Only two lake cycles were inferred from the amino acid data in the Chewaucan basin for the Quaternary period. Shells with the highest ratios correlated with the Eetza Alloformation and the shells with lowest ratios correlate with the Sehoo Alloformation. The amino acid data suggest that Lake Lahontan and Lake Bonneville experienced similar lake-level histories during the past -660 ka. The Sehoo Alloformation in the Lahontan basin broadly correlates with Bonneville Alloformation in the Bonneville basin based on All ratios and radiocarbon dates. The late and early aminozones within the Eetza Alloformation might correlate, respectively, with the Little Valley and Pokes Point Alloformations in the Bonneville basin.

abstract: Geochronology and thermochronology are valuable tools for investigating the synergy between the deformational and erosional processes that shape mountainous terrains. Though numerous techniques have been developed to probe the rate and timing of events within these settings, the research presented here explores how scientists can use fewer samples to produce richer data products with broader contextual importance. The beginning of this compilation focuses on establishing laboratory techniques to facilitate this goal. I developed a novel laser ablation ‘double dating’ (LADD) technique that rapidly yields paired U/Pb and (U-Th)/He dates for the accessory minerals zircon, titanite, and apatite. The technique obviates the need for geometric corrections typically applied during (U-Th)/He data reduction, enables the analysis of a broader spectrum of detrital crystals, and provides the opportunity for additional mapping and isotopic analyses that are traditionally challenging to procure and/or fraught with assumptions. Despite the technique’s promise, I also found it essential to weigh several considerations of relevance when attempting to date young (≤ Miocene) accessory minerals with low concentrations of U + Th. Consequently, I discuss the impact that such variables have on the magnitude of analytical imprecision and the data’s flexibility for geologic interpretation. Beyond the lab, I collected a suite of bedrock and detrital samples from small catchments draining the southeastern Sierra Nevada mountains of California. Using the techniques described above as well as conventional methods for (U-Th)/He zircon dating, I compared the utility of both bedrock and detrital approaches for extrapolating local exhumation histories. I additionally tested the ability to employ detrital datasets to extrapolate cooling histories that span from mineral crystallization to rock exhumation through the upper crust. Employing principal mode dates from a combination of zircon and apatite LADD dates and detrital hornblende 40Ar/39Ar dates, I was able to derive thermal models that demonstrate the existence of significant variability in the cooling histories of various intrusive units along the eastern Sierra Nevada. While these results only scratch the surface of what’s possible within the realm of detrital-based research, this contribution demonstrates the utility of expanding the temporal and spatial scope of traditional detrital methodologies. / Dissertation/Thesis / Doctoral Dissertation Geological Sciences 2019

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