Agro-biodiversity in the desert oases of Baja California, Mexico is a product of isolation and integration through time and across the various spaces of the peninsula. The oases hold heirloom perennial crop species first introduced by Jesuit missionaries (1697-1768) and represent geographies of historical dissemination. I selected fifteen Jesuit mission oases and surveyed the oasis gardens for species richness and abundance. To understand the cultural, political and economic forces that create these patterns of persistence within the oases, I conducted interviews on farming system practices, geographical remoteness, market integration, land tenure, tourism, protected area status and cultural practices. In all, I surveyed 241 gardens and documented eighty-nine total perennial crop species. Historical records in 1774 describe twenty-one perennial crop species in cultivation after the Jesuit expulsion. I calculated species-area relationships and rank-abundance for total perennial and mission crop species in each oasis and inventory comparisons for those oases with quantitative historical data to analyze retention of historic mission species. A high persistence of mission species indicates that oases serve as agro-biodiversity refugia, or protected source areas for agricultural species. These mission-oases act as a network of interconnected sites that are also isolated from one another and the Mexican mainland by the rugged environment, limited transportation infrastructure, and by sea. Within the network, these fifteen oases span a range of small and hours distant from the nearest resource center, to fully urbanized with international ports and airports. I describe how phases and processes of isolation and connectivity shape and transform the agro-biodiversity profiles in this archipelago of peninsula oases.

Sound propagation in very shallow water is one of the issues of the ocean acoustic. Because of close distance to the shore and short range to the bottom, the building of sound propagation model in shallow water is much more difficult than in deep water. Even though, the increasing needs of upper-sea construction engineering and near-shore surveillance make this subject more and more important. This study is to build a high sensitive underwater recording system, use it to collect data and to find out which parameters affect the sound propagation in very shallow water most. The study contains underwater recording system construction, shallow water recording experiment and comparison of OASES simulation results and the collective data. The system is constructed with two ITC6050C hydrophones and data acquisition devices. After several tests of reliability, the system is put in the sea area about 10 m depth. And the two hydrophones were moored 1 m above the bottom and 2.5 m below sea surface separately. The experiment use a moving fishing boat motor noise as sound source and the experimental results are shown as the spectrogram of sound field. The computer simulation uses OASES modules to simulate the experimental area and Pekeris waveguide propagation as the theoretical environment of very shallow water. By comparing the simulation results and the collective data ,the study finds out that the major parameters of sound propagation in the experimental area are the pressure sound speed and the depth of the sound source.

Thesis (doctoral)--University of Bergen, 1979. / Includes bibliographical references and index.

Thesis (doctoral)--University of Bergen, 1979. / Includes bibliographical references and index.

No description available.

Reverberation is the phenomenon when the sound source transmits and causes scattering in active sonar system. This kind of effects often produced in the waveguide, resulting signal interference and signal mask issues. Reverberation can affect the signal to noise ratio, thus understanding the characteristic of environmental reverberation is important. In recent years, there were many studies for the Sizihwan Bay Marine Test Field (MTF), including environmental surveys, Harbor defense and acoustic inversion, however the issue related to reverberation has not been explored. The purpose of this study is to research reverberation in the MTF and focusing on volume reverberation and surface reverberation. In the past, the experiment of Underwater Intruder Detection with active sonar system demonstrated the reverberation in Kaohsiung second harbor. Therefore, this research is about using the experimental data to questions about volume reverberation. Results show, volume reverberation in the port area caused by ship, boundaries, current, impurities in water and biota. On the other hand surface reverberation, this study focusing on numerical simulation, match the results of experimental. Numerical results of RMS height, correlation length and frequency affect the reverberation intensity, but it does not identify the phenomenon of reverberation in experimental results, mainly is the intensity of the source is not enough. This study combined with simulation and experiment, and overviewed the reverberation properties in MTF. Also provided suggestions for following studies.

The purpose of this study explores the sound propagation in very shallow water to understand the environment quality of the Si-Tzi Marine Test Field. Very shallow water acoustics characterized by that sound wave will have a dramatic interaction between the bottoms and the propagation of wave and bottom with a high degree of correlation. Those types of environment are concentrated in the west coast of Taiwan. Analysis of actual acoustic data from the ocean obtain and to use "OASES" simulation that an applied acoustic tool. Expect to understand the phenomenon of water acoustic propagation in the very shallow. The Si-Tzi marine test field had detailed environmental information by previously study. In experiment process, the hydrophone "iTC-6050c" receiving broadband sound source "UW350" signal. The use of personal computer with DAQ card for data acquisition and control. The source in the research vessel was moored 20 m below sea, at the same time to launch three consecutive single (frequency signal 350 Hz, 800 Hz, and 1250 Hz). Reception of signals in order to drift the way. Measured at different frequencies in very shallow water of the transmission loss. The results showed that the results of the current measurement and simulation in line with the follow-up study will be measured "transmission loss" to do to Inversion for geoacoustic parameters in very shallow water. Then obtained "geoacoustic parameters" Comparison of sea-bed surface sampling results. Confirmation "geoacoustic inversion technique" is correct.

Texte remanié de : Thèse 3e cycle : Sociologie : Paris V : 1981. / Bibliogr. p. 407-415 . Index.

Cette thèse porte sur un espace oasien (une terre agricole encore en état de production) qui tend à s’urbaniser de manière informelle : l’oasis de Zrig, dans le Sud-est de Gabès, en Tunisie. L’habitat qui s’y développe prolifère sans permis de construire depuis 1980. Dans ce nouvel espace urbain se développe une double marginalisation sociale touchant aussi bien les paysans qui ont perdu leurs terres que les nouveaux venus aux ressources souvent précaires. L’environnement et le patrimoine agricole local en pâtissent également. Zrig est un détail (au sens pictural) du devenir de l’oasis de Gabès. Un travail de recherche sur l’espace de Zrig et ses transformations se rapproche de la chronique d’une dégradation annoncée. Il y a, en effet, dégradation à deux niveaux : la transformation d’un espace oasien en un espace urbain difforme et le développement de pratiques socio-économiques informelles liées aux stratégies des nouveaux arrivants et aux rapports qu'ils entretiennent avec les autorités locales.Ce travail s’appuie sur les résultats d’une enquête de longue haleine que j'ai effectuée de 2010 au 2016 auprès des habitants de Zrig, ceux d’hier et d’aujourd’hui, afin de recueillir leurs représentations des transformations spatiales et sociales qui ont affecté l’oasis. Il constitue également une étude des modes de construction de logements informels et une analyse des stratégies perpétuant cette pratique mise en œuvre par les nouveaux venus. / This dissertation relates to an oasis area (a still productive agricultural land) which is being informally urbanized: in the Zrig oasis, south-east of Gabes, the habitat has proliferated without building permit since 1980.In this new urban space, a double social marginalization affects farmers who lost their land as well as newcomers with often precarious resources. The environment and the local agricultural heritage are also impacted.Zrig is a detail (in apictorial sense) of the future of the Gabes oasis. A research work on the space of Zrig and its transformations resembles the chronicle of an announced degradation. Indeed, the degradation can be identified at two levels: the transformation of an oasis area into a deformed urban space, and the development of informal socio-economic practices related to the strategies of space occupants and to their relations with local authorities. In addition to the data provided by official and academic surveys, this work is based on the results of a long-term survey that I conducted from 2010 to 2016 Zrig, those of yesterday and those of today, in order to collect their representations of the spatial and social transformations that affected the oasis. But also to study the building practices of informal settlement sand the strategies of newcomers for this purpose.

Ce mémoire reconstitue l’histoire des théories, modèles et hypothèses qui ont été formulés, principalement en archéologie, afin d’expliquer la naissance de l’agriculture qui correspond, du point de vue chronologique, à la transition (ou révolution) néolithique. Ces schèmes explicatifs sont décrits chronologiquement depuis la naissance de l’archéologie préhistorique, dans la première moitié du XIXe siècle, jusqu’à maintenant. Ils sont classifiés en fonction des principales écoles qui ont joué un rôle prédominant en archéologie préhistorique depuis son origine, soit : l’évolutionnisme multilinéaire, l’école culturelle-historique, le processualisme, le néodarwinisme et le postprocessualisme. Les théories spécifiques (dites de « niveau mitoyen » ou « régionales ») qui ont été avancées par ces écoles sont présentées dans leur ordre chronologique, soit (principalement) : les théories de la dessiccation ou de l’oasis, des flancs de colline, de la périphérie, du stress démographique, du festin compétitif, de la révolution des symboles, etc. Ce mémoire pose enfin les jalons d’une théorie multifactorielle qui intègre ou synthétise les principaux facteurs qui ont pu influer sur la naissance de l’agriculture et sur la transition néolithique. / This dissertation reconstructs the history of theories, models and hypotheses which have been proposed in order to explain the birth of agriculture, that is the neolithic transition or revolution. These explanatory schemes are described chronologically from the birth of prehistoric archaeology, in the first half of the 19th century, until today. They are classified according to the main schools which have played a leading role in prehistoric archaeology since its birth: multilinear evolutionism, the culture-historical school, processualism, neodarwinism and postprocessualism. The specific theories (also called “middle-range” or “regional”) which have been proposed by these schools are presented the chronological order: the theories of desiccation, oases, hilly flanks, periphery, population stress, competitive feasting, revolution of symbols, etc. Finally, this dissertation lays the ground for a multifactorial theory integrating or synthesizing the main factors which may have influenced the birth of agriculture and the neolithic transition.