acase@tulane.edu / --- / 1 / Mira Kohl

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Um estudo gravimétrico comparativo das bacias do Chaco-Paraná (BCP) e Paraná (BP) foi efetuado utilizando o modelo global EGM08 e os dados da missão GOCE. A feição gravimétrica mais notável é um gradiente gravimétrico de 0,25 mGal/km, de direção norte-sul e que contorna a borda oeste da Bacia do Paraná e inflexiona para leste na latitude 30º S. Esse gradiente separa as duas bacias em províncias gravimétricas com características distintas. A BCP é caracterizada por anomalias gravimétricas positivas entre 10 e 20 mGal e de direção norte-sul, enquanto que na BP as anomalias variam entre -50 a -90 mGal na direção NE-SW. A análise gravimétrica foi efetuada de duas formas. Inicialmente removeu-se o efeito gravitacional devido aos sedimentos e basaltos e a anomalia devido às fontes mais profundas foi invertida para determinar o relevo da interface crosta-manto. Posteriormente efetuou-se uma análise isostática estimando a profundidade de compensação para a topografia observada nos modelos de Airy e flexural de placa contínua. Esses modelos, considerando a topografia observada como a única carga, não preveem a profundidade da Moho qualquer que seja o valor da espessura elástica. Dados de profundidade da Moho por métodos sismológicos, onde existentes, foram confrontados com os fornecidos pela inversão gravimétrica, estimando assim o valor do contraste de densidade (300 kg/m³) para o qual as profundidades da Moho e da interface crosta-manto obtida pela gravimetria melhor se ajustam. A inversão gravimétrica indica que a crosta da BCP é em média 7 km menos espessa do que a crosta da BP. Os resultados deste estudo sugerem a existência de uma descontinuidade crustal, e possivelmente uma sutura litosférica ao longo do gradiente gravimétrico entre as bacias do Chaco-Paraná e do Paraná. / A comparative gravity study of the Chaco-Paraná (CPB) and the Paraná (PB) basins was carried out using the EGM08 and GOCE global geopotential models. The most prominent gravity feature in the study area is a gradient of 0.25 mGal/km, extending from north to south alongside the western border of the Paraná basin and continuing eastward towards the Atlantic coast at the latitude 30º S. This gradient separates both basins into two gravity provinces with distinct characteristics. The CPB is marked by positive Bouguer anomalies of about 10 to 20 mGal in amplitude with north-south trending, whereas in the PB the Bouguer anomalies range from -50 to -90 mGal and trend along the NE-SW direction. The gravity analysis was carried out in two ways. Firstly, the gravity effect from basalts and sediments was calculated and removed and the gravity anomaly due to deeper sources was inverted in order to determine the crust-mantle interface relief. Secondly, an isostatic analysis was carried out in order to estimate the compensation depth due to the observed topography using both Airy and continuous plate flexural models. These isostatic models, considering the observed topography as the only load, cannot account for the observed Moho regardless of the effective elastic thickness value. Moho depth provided by seismological studies, where available, were compared with the results of the gravity inversion, thus estimating the density contrast (300 kg/m3) for which the Moho and crust-mantle interface depths are in agreement. The gravity inversion indicates that, in average, the CPB crust is 7 km thinner than the PB crust. This study suggests the existence of a crustal discontinuity, and perhaps even a lithospheric suture along the gravity gradient between the Chaco-Paraná and the Paraná basins.

Um estudo gravimétrico comparativo das bacias do Chaco-Paraná (BCP) e Paraná (BP) foi efetuado utilizando o modelo global EGM08 e os dados da missão GOCE. A feição gravimétrica mais notável é um gradiente gravimétrico de 0,25 mGal/km, de direção norte-sul e que contorna a borda oeste da Bacia do Paraná e inflexiona para leste na latitude 30º S. Esse gradiente separa as duas bacias em províncias gravimétricas com características distintas. A BCP é caracterizada por anomalias gravimétricas positivas entre 10 e 20 mGal e de direção norte-sul, enquanto que na BP as anomalias variam entre -50 a -90 mGal na direção NE-SW. A análise gravimétrica foi efetuada de duas formas. Inicialmente removeu-se o efeito gravitacional devido aos sedimentos e basaltos e a anomalia devido às fontes mais profundas foi invertida para determinar o relevo da interface crosta-manto. Posteriormente efetuou-se uma análise isostática estimando a profundidade de compensação para a topografia observada nos modelos de Airy e flexural de placa contínua. Esses modelos, considerando a topografia observada como a única carga, não preveem a profundidade da Moho qualquer que seja o valor da espessura elástica. Dados de profundidade da Moho por métodos sismológicos, onde existentes, foram confrontados com os fornecidos pela inversão gravimétrica, estimando assim o valor do contraste de densidade (300 kg/m³) para o qual as profundidades da Moho e da interface crosta-manto obtida pela gravimetria melhor se ajustam. A inversão gravimétrica indica que a crosta da BCP é em média 7 km menos espessa do que a crosta da BP. Os resultados deste estudo sugerem a existência de uma descontinuidade crustal, e possivelmente uma sutura litosférica ao longo do gradiente gravimétrico entre as bacias do Chaco-Paraná e do Paraná. / A comparative gravity study of the Chaco-Paraná (CPB) and the Paraná (PB) basins was carried out using the EGM08 and GOCE global geopotential models. The most prominent gravity feature in the study area is a gradient of 0.25 mGal/km, extending from north to south alongside the western border of the Paraná basin and continuing eastward towards the Atlantic coast at the latitude 30º S. This gradient separates both basins into two gravity provinces with distinct characteristics. The CPB is marked by positive Bouguer anomalies of about 10 to 20 mGal in amplitude with north-south trending, whereas in the PB the Bouguer anomalies range from -50 to -90 mGal and trend along the NE-SW direction. The gravity analysis was carried out in two ways. Firstly, the gravity effect from basalts and sediments was calculated and removed and the gravity anomaly due to deeper sources was inverted in order to determine the crust-mantle interface relief. Secondly, an isostatic analysis was carried out in order to estimate the compensation depth due to the observed topography using both Airy and continuous plate flexural models. These isostatic models, considering the observed topography as the only load, cannot account for the observed Moho regardless of the effective elastic thickness value. Moho depth provided by seismological studies, where available, were compared with the results of the gravity inversion, thus estimating the density contrast (300 kg/m3) for which the Moho and crust-mantle interface depths are in agreement. The gravity inversion indicates that, in average, the CPB crust is 7 km thinner than the PB crust. This study suggests the existence of a crustal discontinuity, and perhaps even a lithospheric suture along the gravity gradient between the Chaco-Paraná and the Paraná basins.

Thesis (Ph. D.)--Bryn Mawr college. / Bibliography; p. 145-152.

En este trabajo se realizaron estimaciones de abundancia y densidad de la población de primates en el bosque del río Parapeti en la TCO del Isoso a través de transectas lineales. Las transectas, con un recorrido total de 872 km, fueron distribuidas en las comunidades de Karapari, La Brecha y Kuarirenda con 3 sendas en cada una con 4 km de longitud. La abundancia relativa se analizó tomando el número de encuentros por 10 km de recorrido simple. La densidad en la población de monos se estimó con el programa DISTANCE 4.0. En bosque ribereño, los recorridos por transectas diurnas lograron tener el mayor número de encuentros por grupos de las especies ururo (Callicebus pallescens) seguido por el caraya (Alouatta caraya), luego el cuatro ojos (Aotus azarae) y finalmente se tuvieron menor cantidad de encuentros con el mono martín (Cebus libidinosus).

Chacoan great houses have been described as providing "ritual" or "integrative" venues and as "monumental" in scale and in the amount of labor required for their construction. This study takes the approach that part of the function of community, monumental, or ritual structures is to transmit meaning and that an examination of visibility connections between these structures and small habitation sites in the surrounding community may provide information about the role of these messages in daily practice. Survey data from the Chacoan community at Kin Bineola, New Mexico is analyzed in a GIS environment using a model of visibility and distance developed for this project. The results show that, contrary to expectations, the great house is much less visible than a less monumental "Chacoan structure." Shrines, small structures interpreted as having a ritual function, are by far the most visible, suggesting a more complex relationship between monumentality and visibility.

Diss.--Philosophisch-historische Fakultät--Basel, 1979. / Résumé en anglais. Bibliogr. p. 416-430. Index.

Large-scale, multispecies monitoring programs are used widely to assess changes in wildlife populations; however, they often assume constant detectability when documenting species occurrence. This assumption is rarely accurate because animal populations vary considerably across time and space. Furthermore, detectability of a species can be influenced by a number of physical, biological, or anthropogenic factors (e.g., weather, seasonality, topography, sampling methods, urban development). Analyses of habitat factors affecting occupancy and detection of mammalian species have not been conducted in the Paraguayan Chaco. To address this gap in the literature and provide conservation recommendations, I estimated site occupancy rates using species-specific detection probabilities for focal mammalian species at 3 study sites in the Chaco ecoregion of Paraguay. During remote camera surveys conducted August - November 2011 - 2012, I used photographic data and model selection techniques to assess the influence of different survey and site covariates on occupancy of several focal mammalian species: maned wolf (Chrysocyon brachyurus), Geoffroy's cat (Leopardus geoffroyi), puma (Puma concolor), crab-eating fox (Cerdocyon thous), pampas fox (Lycalopex gymnocercus), collared peccary (Pecari tajacu), white-lipped peccary (Tayassu pecari), South American tapir (Tapirus terrestris), and giant anteater (Myrmecophaga tridactyla). I recorded 2,034 photographs of 24 mammalian species at 64 camera sites; among those, 1,353 photographs and 529 independent survey-detections were of these 9 focal species. Detection of maned wolves and peccaries was higher in 2011 than 2012; other species did not show significant differences in detection by year. Peccaries were detected more frequently during higher temperatures, but foxes were detected more frequently during lower temperatures. The crab-eating fox was the species occupying the most sites (68%) and white-lipped peccary was the rarest, occupying only 30% of the study area. Anthropogenic disturbances (i.e., urban areas, paved roads, and human structures) negatively affected most species. Maned wolves and collared peccaries appeared to prefer grasslands, while puma and crab-eating fox used areas closer to water. White-lipped peccaries appeared to be most common or widely-distributed at the Toro Mocho study site. My research will provide land managers and conservation planners with an understanding of how mammals are distributed across the Paraguayan Chaco, as well as informing future decisions concerning land use and development by the rural human population. To further broad-scale conservation goals, wildlife biologists in Paraguay should seek partnerships with rural stakeholders to mitigate the effects of continuing agro-industrial development. Moreover, additional protected areas and buffers should be sought to maintain lands in natural conditions, including large areas set aside as wildlife reserves.

My thesis examines from an ethnographic account how history has been made, told and interpreted by the Angaité people of the Chaco since the Paraguayan nation-state effectively carried out the colonization of this territory in the 19th century until the present day. The key elements of this account are the Angaité’s notions and practices on alterity, storytelling and shamanism and how they interplay with one another. I explore the notions of alterity and its counterpart similarity in the context of multiple material transactions in which the Angaité engage both among themselves and with outsiders. I also examine the inseparable socio-moral evaluations attached to such transactions. I show how certain transactions such as exchange or commoditisation do not necessarily conflict with good social relations. Nevertheless, the closest relationships – preferably evoked in kinship terms - are constantly constructed by the combination of several practices including sharing, pooling, cohabitation and companionship and the relational morality that underpins them. This relational morality, I argue, is both inscribed and enacted through the telling of Nanek Any’a narratives –“Old news/events”. I analyze some of these narratives in order to show how the Angaité people interpret the consequences of the colonization of the Chaco. For this I provide an intelligible context for the Nanek Any’a that may otherwise appear contradictory or incomprehensible to a non-Angaité listener. The Angaité’s versions of history compared to the official accounts challenge the simplistic of the Angaité as “acculturated” and a homogenous indigenous people and situate them as main actors of their own lives. Rather than the Angaité being the victims of history the Nanek Any’a emphasize that it was the mistakes and failing of their ancestors in their original encounter with the Paraguayans that resulted in an unbalanced relationship with the latter in socio-economic terms. In addition to this, I describe in the light of the historical processes undergone in the lives of the Angaité, how the shamanic discourses and capacities and Angaité cosmology have changed. I explore how they have constantly incorporated external elements, and thus such shamanic elements pervades contemporary areas of life and interactions that include not only the paradigmatic indigenous shaman, but unusual figures such as pastors, powerful outsiders and leaders.