Thesis (Ph. D.)--Harvard University, 1970. / Includes bibliographical references (p. 286-319).

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Inputs, transfer processes, and storage characteristics of water and sediment have been investigated in a 40-km² estuarine system on the central Yukon coast. The setting is transgressive, microtidal, and high-latitude (69°N). The Babbage Estuary system can be subdivided into fluvial, tidal-distributary, delta-plain, intertidal, lagoon, marginal-supratidal, and barrier subsystems, each associated with one or more distinctive depositional environments and characteristic lithofacies assemblages. The structure of the system has been examined in terms of links between subsystems and overall system response to input perturbations. Although the propagation of tide and surge within the estuary may be treated as a quasi-linear stochastic process, transfers of fluvial water and sediment through the system are highly non-linear. Furthermore, the parameters of the system change dramatically on an annual cycle. Inputs and associated system responses are dominated in the short run by seasonal- and synoptic-scale variance, the former reflecting major seasonal adjustments in the phase distribution, circulation process, iand input regime of the estuary. The annual salinity cycle, with a range of at least 60 ppt, exhibits a short reaction and long relaxation response to major snowmelt runoff inputs in May or June, when salt water is flushed completely out of the estuary. Wind-generated waves are effectively absent from the system during 8-9 months of the year, but play a major role during the open-water season. Although direct transport of sediment by ice is relatively unimportant, ice effects are pervasive; they include, in addition to restriction of winter runoff and surface wave generation, creation of hypersaline conditions, control of the sedimentologically important flood events on deltaic supratidal flats, enhanced rates of coastal recession due to thermal degradation of ground ice, and production of distinctive thermokarst morphology on supratidal surfaces. Water level, storage volume, salinity, and suspended sediment series during the open-water season in the lagoon are dominated by synoptic-scale wind effects. In the delta, the major synoptic-scale anomalies of sediment concentration are related to storm runoff. Fluvial clastic sediment inputs to the estuary exceed 10⁸ kg A⁻¹ almost an order of magnitude greater than the estimated littoral transport input. More than 97% of the fluvial input may occur in June; of this, approximately half may be exported directly from the system. At long time scales, the estuarine system has been dominated by rising sea level and coastal recession; Holocene climatic fluctuations may also have been important. A transgressive sequence has developed, including various distinctive features, notably the absence or limited development of aeolian, backbarrier-margin, tidal-delta, and intertidal marsh facies, a largely afaunal intertidal component, and deltaic deposits with poorly developed levees and abundant lake basins. The basal fluvial component includes a sinuous gravel channel assemblage of a hitherto poorly documented type. The Babbage Estuary barrier sequence is primarily transgressive, but incorporates localized elements of progradational and inlet-migration models. Examples of major transgressive, progradational, and inlet-fill barrier sequences occur in close proximity on the central Yukon coast. / Arts, Faculty of / Geography, Department of / Graduate

Made available in DSpace on 2016-04-28T14:16:16Z (GMT). No. of bitstreams: 1 Eli Banks Liberato da Costa.pdf: 7788655 bytes, checksum: 8a2e3668051ba71d8dfce7fc45af3a33 (MD5) Previous issue date: 2012-10-15 / The theme of the origins of computers has aroused controversies that are not always well enlightened. This paper intends to contribute to the subject focusing on the mechanical calculating machines designed in the first half of the nineteenth century by Charles Babbage (1791-1871). It presents the main motivations of its inventor, his ideas, difficulties and ingenuity to face some completely new and challenging technical problems. We also analyze the French motivations and solution to solve calculus problems. In the context of that time, we examined carefully the question of communication between man and machine, so far an intriguing innovation that generated enthusiasm, controversy and many speculations. We highlight Babbage s perception that there was "some slight analogy to the operation of the faculty of memory", an idea shared by some of his contemporaries. Even at that time, then, the idea of the "thinking machine" arose, ancestor of the more recent idea of the "electronic brain". Finally we refer to the not so expressive Babbage s technical legacy as opposed to a meaningful and engaging fact that he stimulated an opening for a new and fascinating human activity: the dialogue between man and the machine of his creation. Keywords / O tema das origens dos computadores tem despertado controvérsias que nem sempre ficam bem esclarecidas. Este trabalho pretende contribuir com esse assunto focalizando as máquinas calculadoras mecânicas projetadas na primeira metade do século XIX por Charles Babbage (1791-1871). São apresentadas as principais motivações de seu inventor, suas ideias, dificuldades e engenhosidade ao enfrentar alguns problemas técnicos completamente novos e desafiantes. Analisamos também as motivações e solução francesa para resolver os problemas de cálculo. No contexto dessa época, aprofundamo-nos na questão da comunicação do homem com a máquina, então uma intrigante novidade que gerou entusiasmos, controvérsias e muitas especulações. Destacamos a percepção de Babbage de que havia alguma leve analogia com as faculdades da memória , ideia compartilhada com alguns de seus contemporâneos. Surge então, já naquela época, a ideia da máquina de pensar , ancestral da idéia mais recente do cérebro eletrônico . Finalmente referimo-nos ao não tão expressivo legado técnico de Babbage em contraposição a um significativo e envolvente fato dele ter estimulado uma abertura para uma nova e fascinante atividade humana: o diálogo do homem com a máquina de sua criação