17 resultados para rotation invariance


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Dissertação apresentada como requisito parcial para obtenção do grau de Mestre em Estatística e Gestão de Informação

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The evolution of the Lusitanian Basin, localized on the western Iberian margin, is closely associated with the first opening phases of the North Atlantic. It persisted from the Late Triassic to the Early Cretaceous, more precisely until the end of the Early Aptian, and its evolution was conditioned by inherited structures from the variscan basement. The part played by the faults that establish its boundaries, as regards the geometric and kinematic evolution and the organization of the sedimentary bodies, is discussed here, as well as with respect to important faults transversal to the Basin. A basin evolution model is proposed consisting of four rifting episodes which show: i) periods of symmetrical (horst and graben organization) and asymmetrical (half graben organization) geometric evolution; ii) diachronous fracturing; iii) rotation of the main extensional direction; iv) rooting in the variscan basement of the main faults of the basin (predominantly thick skinned style). The analysis and regional comparison, particularly with the Algarve Basin, of the time intervals represented by important basin scale hiatuses near to the renovation of the rifting episodes, have led to assume the occurrence of early tectonic inversions (Callovian–Oxfordian and Tithonian–Berriasian). The latter, however, had a subsequent evolution distinct from the first: there is no subsidence renovation, which is discussed here, and it is related to a magmatic event. Although the Lusitanian Basin is located on a rift margin which is considered non-volcanic, the three magmatic cycles as defined by many authors, particularly the second (approx. 130 to 110 My ?), performed a fundamental part in the mobilization of the Hettangian evaporites, resulting in the main diapiric events of the Lusitanian Basin. The manner and time in which the basin definitely ends its evolution (Early Aptian) is discussed here. Comparisons are established with other west Iberian margin basins and with Newfoundland basins. A model of oceanization of this area of the North Atlantic is also presented, consisting of two events separated by approximately 10 My, and of distinct areas separated by the Nazaré fault. The elaboration of this synthesis was based on: - information contained in previously published papers (1990 – 2000); - field-work carried out over the last years, the results of which have not yet been published; - information gathered from the reinterpretation of geological mapping and geophysical (seismic and well logs) elements, and from generic literature concerning the Mesozoic of the west iberian margin.

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The Author presents a synopsis about the post-Paleozoic igneous activity in continental Portugal. Subvolcanic massifs of Sintra, Sines and Monchique and the basaltic complex of Lisbon-Mafra are interpreted. The large network of dikes and sills occuring at north of Tagus river in Lisbon- Torres Vedras region as the dikes of Algarve and also those of diapiric formation are studied and compared. Also the doleritic dikes cuting the Hesperic Massif and the Great dike of Alentejo are studied. The Author presents an attempt of petrological and geochemical correlation-among these post-Paleozoic igneous rocks. For this more than 350 chemical analysis are used in order to elaborate several diagrams and some general conclusions are derived from them. The correlation between the origin of these igneous rocks and the opening of North Atlantic and the counter-clockwise rotation of the Iberia are also tried.

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(l) The Pacific basin (Pacific area) may be regarded as moving eastwards like a double zip fastener relative to the continents and their respective plates (Pangaea area): opening in the East and closing in the West. This movement is tracked by a continuous mountain belt, the collision ages of which increase westwards. (2) The relative movements between the Pacific area and the Pangaea area in the W-EfE-W direction are generated by tidal forces (principle of hypocycloid gearing), whereby the lower mantle and the Pacific basin or area (Pacific crust = roof of the lower mantle?) rotate somewhat faster eastwards around the Earth's spin axis relative to the upper mantle/crust system with the continents and their respective plates (Pangaea area) (differential rotation). (3) These relative West to East/East to West displacements produce a perpetually existing sequence of distinct styles of opening and closing oeean basins, exemplified by the present East to West arrangement of ocean basins around the globe (Oceanic or Wilson Cycle: Rift/Red Sea style; Atlantic style; Mediterranean/Caribbean style as eastwards propagating tongue of the Pacific basin; Pacific style; Collision/Himalayas style). This sequence of ocean styles, of which the Pacific ocean is a part, moves eastwards with the lower mantle relative to the continents and the upper-mantle/crust of the Pangaea area. (4) Similarly, the collisional mountain belt extending westwards from the equator to the West of the Pacific and representing a chronological sequence of collision zones (sequential collisions) in the wake of the passing of the Pacific basin double zip fastener, may also be described as recording the history of oceans and their continental margins in the form of successive Wilson Cycles. (5) Every 200 to 250 m.y. the Pacific basin double zip fastener, the sequence of ocean styles of the Wilson Cycle and the eastwards growing collisional mountain belt in their wake complete one lap around the Earth. Two East drift lappings of 400 to 500 m.y. produce a two-lap collisional mountain belt spiral around a supercontinent in one hemisphere (North or South Pangaea). The Earth's history is subdivided into alternating North Pangaea growth/South Pangaea breakup eras and South Pangaea growth/North Pangaea breakup eras. Older North and South Pangaeas and their collisional mountain belt spirals may be reconstructed by rotating back the continents and orogenic fragments of a broken spiral (e.g. South Pangaea, Gondwana) to their previous Pangaea growth era orientations. In the resulting collisional mountain belt spiral, pieced together from orogenic segments and fragments, the collision ages have to increase successively towards the West. (6) With its current western margin orientated in a West-East direction North America must have collided during the Late Cretaceous Laramide orogeny with the northern margin of South America (Caribbean Andes) at the equator to the West of the Late Mesozoic Pacific. During post-Laramide times it must have rotated clockwise into its present orientation. The eastern margin of North America has never been attached to the western margin of North Africa but only to the western margin of Europe. (7) Due to migration eastwards of the sequence of ocean styles of the Wilson Cycle, relative to a distinct plate tectonic setting of an ocean, a continent or continental margin, a future or later evolutionary style at the Earth's surface is always depicted in a setting simultaneously developed further to the West and a past or earlier style in a setting simultaneously occurring further to the East. In consequence, ahigh probability exists that up to the Early Tertiary, Greenland (the ArabiaofSouth America?) occupied a plate tectonic setting which is comparable to the current setting of Arabia (the Greenland of Africa?). The Late Cretaceous/Early Tertiary Eureka collision zone (Eureka orogeny) at the northern margin of the Greenland Plate and on some of the Canadian Arctic Islands is comparable with the Middle to Late Tertiary Taurus-Bitlis-Zagros collision zone at the northern margin of the Arabian Plate.

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Cretaceous Research 30 (2009) 575–586

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(l) The Pacific basin (Pacific area) may be regarded as moving eastwards like a double zip fastener relative to the continents and their respective plates (Pangaea area): opening in the East and closing in the West. This movement is tracked by a continuous mountain belt, the collision ages of which increase westwards. (2) The relative movements between the Pacific area and the Pangaea area in the W-E/E-W direction are generated by tidal forces (principle of hypocycloid gearing), whereby the lower mantle and the Pacific basin or area (Pacific crust = roof of the lower mantle?) rotate somewhat faster eastwards around the Earth's spin axis relative to the upper mantle/crust system with the continents and their respective plates (Pangaea area) (differential rotation). (3) These relative West to East/East to West displacements produce a perpetually existing sequence of distinct styles of opening and closing ocean basins, exemplified by the present East to West arrangement of ocean basins around the globe (Oceanic or Wilson Cycle: Rift/Red Sea style; Atlantic style; Mediterranean/Caribbean style as eastwards propagating tongue of the Pacific basin; Pacific style; Collision/Himalayas style). This sequence of ocean styles, of which the Pacific ocean is a part, moves eastwards with the lower mantle relative to the continents and the upper-mantle/crust of the Pangaea area. (4) Similarly, the collisional mountain belt extending westwards from the equator to the West of the Pacific and representing a chronological sequence of collision zones (sequential collisions) in the wake of the passing of the Pacific basin double zip fastener, may also be described as recording the history of oceans and their continental margins in the form of successive Wilson Cycles. (5) Every 200 to 250 m.y. the Pacific basin double zip fastener, the sequence of ocean styles of the Wilson Cycle and the eastwards growing collisional mountain belt in their wake complete one lap around the Earth. Two East drift lappings of 400 to 500 m.y. produce a two-lap collisional mountain belt spiral around a supercontinent in one hemisphere (North or South Pangaea). The Earth's history is subdivided into alternating North Pangaea growth/South Pangaea breakup eras and South Pangaea growth/North Pangaea breakup eras. Older North and South Pangaeas and their collisional mountain belt spirals may be reconstructed by rotating back the continents and orogenic fragments of a broken spiral (e.g. South Pangaea, Gondwana) to their previous Pangaea growth era orientations. In the resulting collisional mountain belt spiral, pieced together from orogenic segments and fragments, the collision ages have to increase successively towards the West. (6) With its current western margin orientated in a West-East direction North America must have collided during the Late Cretaceous Laramide orogeny with the northern margin of South America (Caribbean Andes) at the equator to the West of the Late Mesozoic Pacific. During post-Laramide times it must have rotated clockwise into its present orientation. The eastern margin of North America has never been attached to the western margin of North Africa but only to the western margin of Europe. (7) Due to migration eastwards of the sequence of ocean styles of the Wilson Cycle, relative to a distinct plate tectonic setting of an ocean, a continent or continental margin, a future or later evolutionary style at the Earth's surface is always depicted in a setting simultaneously developed further to the West and a past or earlier style in a setting simultaneously occurring further to the East. In consequence, ahigh probability exists that up to the Early Tertiary, Greenland (the ArabiaofSouth America?) occupied a plate tectonic setting which is comparable to the current setting of Arabia (the Greenland of Africa?). The Late Cretaceous/Early Tertiary Eureka collision zone (Eureka orogeny) at the northern margin of the Greenland Plate and on some of the Canadian Arctic Islands is comparable with the Middle to Late Tertiary Taurus-Bitlis-Zagros collision zone at the northern margin of the Arabian Plate.

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The present work follows a stratigraphic model for the marine Neogene of Portugal based on the definition of three main marine sedimentary cycles. Conceptually the I, II and III Neogene Cycles can be defined as 2nd order sedimentary sequences with duration ranging from 5 to 8 Ma. The I Neogene Cycle is fully represented only in the Lower Tagus Basin. Ranging from the Early Aquitanian to the Late Burdigalian the I Neogene Cycle testify a transgressive episode in the region of Lisbon and Setúbal Peninsula. Rapid lateral facies variations suggest a shallowmarine basin. This cycle ends with an important Late Burdigalian tectonic compressive event expressed by uplift of the surrounding areas and deformation affecting the Early Miocene deposits of the Arrábida Chain. The II Neogene Cycle includes thick sedimentary sequences covering Paleozoic and Mesozoic formations in the Algarve and Alvalade-Melides regions and it extends as far north as Santarém in the Lower Tagus Basin. Mainly controlled by global eustasy, it was generated by the important positive eustatic trend that characterized the Middle Miocene worldwide to which the Portuguese continental margin acted more or less passively. This cycle ended with a second and the most important compression event starting after the end of the Serravallian affecting the entire Portuguese onshore and shelf areas. This led to an important depositional hiatus of marine sediments for more than 2.5 Ma. During the Early and the Middle Tortonian occurred the clockwise rotation of the Guadalquivir Basin. The thickmarine units deposited afterwards in this basin produced a litostatic load, which seems to have induced subsidence farther west resuming the Neogene marine sedimentation in the Cacela region (Eastern Algarve), during the Late Tortonian. This marks the beginning of the III Neogene Cycle. To the north, in the Sado Basin (Alvalade-Melides region), a similar depositional sequence starts its sedimentation during the Messinian. Further north, in the Pombal-Caldas da Rainha region, marine sedimentation started during the Late Pliocene (Piacenzian). The migration in time, from south to north for the beginning of the marine sedimentation of this cycle is interpreted as reflecting a visco-elastic propagation of the deformation from the Betic chain northwards.

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RESUMO: A cefaleia cervicogénica é uma forma comum de dor de cabeça, que tem sido associada à existência de uma disfunção das estruturas da coluna cervical superior. Estudos recentes mostram uma grande incidência dessa disfunção a nível de C1-C2, avaliada pelo teste de flexão-rotação. Vários terapeutas manuais, como Brian Mulligan e Mariano Rocabado, têm sido sugerido técnicas de tratamento para este tipo de disfunção. Contudo, a evidência acerca da efectividade dessas técnicas é escassa. Desenho do estudo: Foi efectuado um ensaio clínico aleatório, duplamente cego, composto por três fases: pré-intervenção, intervenção e pós-intervenção. Objectivos: Avaliar e comparar os efeitos imediatos de duas técnicas de Terapia Manual Ortopédica (SNAG C1/2 de Mulligan e técnica de desrotação do atlas de Rocabado), na amplitude de movimento de rotação do segmento vertebral C1-C2, em indivíduos com história de cefaleia cervicogénica e com limitação no teste de flexão-rotação. As técnicas de tratamento foram usadas de forma isolada, em comparação a um grupo placebo. Métodos: Uma amostra de 60 indivíduos, com cefaleia cervicogénica e limitação do teste de flexão-rotação, foram aleatoriamente distribuídos por três grupos: SNAG C1/2 de Mulligan, técnica de desrotação do atlas de Rocabado e grupo placebo. O outcome primário foi a amplitude de movimento obtida no teste de flexão-rotação, que foi medido antes e imediatamente após a intervenção. Resultados: Imediatamente após a intervenção, a amplitude verificada no teste de flexão-rotação aumentou 21.8º (DP, 4.68) no grupo submetido ao SNAG C1/2 de Mulligan, 15º (DP, 5.07) no grupo em que foi aplicada a técnica de desrotação do atlas de Rocabado e 0.65º (DP, 0.67) no grupo placebo. Uma ANOVA modelo misto, 2 por 3, revelou efeito principal significativo do tempo (p<.001) e grupo (p<.001), assim como uma interacção significativa entre grupo e tempo (p<.001), relativamente à variável amplitude do teste de flexão-rotação. Estes resultados indicam que as diferenças verificadas entre os grupos eram dependentes do momento de avaliação. Uma comparação múltipla post hoc revelou que quer as técnicas de Mulligan, quer de Rocabado, produziram efeitos significativamente maiores que a intervenção placebo na amplitude de movimento do teste de flexão-rotação (p<.001 e p=.001, respectivamente). No entanto,não se verificou uma diferença significativa no que diz respeito à efectividade de ambas as técnicas de Terapia Manual Ortopédica aplicadas (p=.42). Conclusão: Esta investigação sugere que as duas técnicas de Terapia Manual Ortopédica avaliadas produziram efeito clínica e estatisticamente significativo na amplitude do teste de flexão-rotação. No entanto, não se verificaram diferenças entre as duas técnicas, no que diz respeito ao seu efeito no ganho de amplitude de movimento. Os resultados obtidos fornecem evidência preliminar sobre a efectividade de ambas as intervenções no tratamento da redução de amplitude de movimento em indivíduos com história de cefaleia cervicogénica.-------------------------------ABSTRACT:Background: Cervicogenic headache is a common form of headache arising from dysfunction in structures of the upper cervical spine. Recent studies have shown a high incidence of C1/2 dysfunction, evaluated by the flexion-rotation test (FRT). Several manual therapists have suggested different approaches to manage that dysfunction, such as Brian Mulligan and Mariano Rocabado. However, the evidence of the effectiveness of those manual techniques is anedoctal. Design: Randomized double blinded controlled trial with three phases: pre-intervention, intervention and post-intervention. Objectives: To determine and compare the immediate effects of two manual therapy techniques (Mulligan’s SNAG C1/2 and Rocabado’s atlas’ derotation technique) in the range of motion of C1-C2 vertebral segments, in cervicogenic headache patients and with limitation on the flexion-rotatoin test. The treatment techniques were used as single treatments against a placebo group. Methods: A sample of 60 subjects with cervicogenic headache and FRT limitation were randomly allocated into one of three groups: Mulligan’s C1/2 SNAG, Rocabado’s atlas derotation technique or placebo group. The primary outcome was the flexion rotation test range, which was measured before and immediately after the intervention. Results: Immediately after the application of the interventions, FRT range increased by 21.8º (SD, 4.68) for the Mulligan’s C1-2 SNAG group, 15º (SD, 5.07) for the Rocabado’s atlas derotation technique and 0.65º (SD, 0.67) for the placebo group. A 2-by-3 mixedmodel ANOVA a significant main effect of time (p<.001) and group (p<.001), as well as a significant interaction between group and time (p<.001) for the variable FRT range. These results indicate that group differences were dependent on time. A pairwise post hoc comparison revelad that both the Mulligan and Rocabado techniques produced significantly more effect on FRT range of motion than the placebo intervention (p<.001 and p=.001, respectively). However, there was not a significant difference between the effectiveness of the two manual therapy techniques (p=.42).Conclusion: This investigation’s findings suggest that both Mulligan’s C1/2 SNAG and Rocabado’s atlas derotation techniques produced a clinically and statistically significant effect on FRT range, but there were no changes between the two techniques in their effectiveness. These results provide preliminary evidence for the efficacy of both manual therapy techniques in the management of individuals with cervicogenic headache and FRT limitation.

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Dissertação para a obtenção do grau de Mestre em Engenharia Mecânica

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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do Grau de Mestre em Engenharia Mecânica

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Dissertação para obtenção do Grau de Mestre em Engenharia Biomédica

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This paper has developed a model of a single forest owner operating with perfect foresight in a dynamic open-city environment that allows for switching between alternative competing land uses (forest and urban use) at some point in the future. The model also incorporates external values of an even-aged standing forest in addition to the value of timber when it is harvested. Timber is exploited based on a multiple rotation model a la Faustmann with clear-cut harvesting. In contrast to previous models, our alternative land use to forest land is endogenous. Within this framework, we study the problem of the private owner as well as that of the social planner, when choosing the time to harvest, the time to convert land and the intensity of development. We also examine the extent to which the two-way linkage between urban development and forest management practices (timber production and provision of forest amenities) contributes to economic efficiency and improvements in non-market forest benefits. Finally, we consider policy options available to a regulator seeking to achieve improvements in efficiency including anti-sprawl policies (impact fees and density controls) and forest policies such a yield tax. Numerical simulations illustrate our analytical results.

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This paper examines the effectiveness of urban containment policies to protect forestland from residential conversion and to increase the provision of forest public goods in the presence of irreversible investments and policy uncertainty. We develop a model of a single landowner that allows for switching between competing land uses (forestry and residential use) at some point in the future. Our results show that urban containment policies can protect (even if temporarily) forestland from being developed but must be supplemented with policies that influence the length and number of harvesting cycles if the goal is to increase nontimber benefits. The threat of a development prohibition creates incentives for preemptive timber harvesting and land conversion. In particular, threatened regulation creates an incentive to shorten rotation cycles to avoid costly land-use restrictions. However, it has an ambiguous effect on forestland conversion as the number of rotation cycles can also be adjusted to maximize the expected returns to land. Finally, in the presence of irreversibility, forestland conversion decisions should be done using real option theory rather than net present value analysis

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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Finance from the NOVA – School of Business and Economics

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During drilling operation, cuttings are produced downhole and must be removed to avoid issues which can lead to Non Productive Time (NPT). Most of stuck pipe and then Bottom-Hole Assembly (BHA) lost events are hole cleaned related. There are many parameters which help determine hole cleaning conditions, but a proper selection of the key parameters will facilitate monitoring hole cleaning conditions and interventions. The aim of Hole Cleaning Monitoring is to keep track of borehole conditions including hole cleaning efficiency and wellbore stability issues during drilling operations. Adequate hole cleaning is the one of the main concerns in the underbalanced drilling operations especially for directional and horizontal wells. This dissertation addresses some hole cleaning fundamentals which will act as the basis for recommendation practice during drilling operations. Understand how parameters such as Flowrate, Rotation per Minute (RPM), Rate of Penetration (ROP) and Mud Weight are useful to improve the hole cleaning performance and how Equivalent Circulate Density (ECD), Torque & Drag (T&D) and Cuttings Volumes coming from downhole help to indicate how clean and stable the well is. For case study, hole cleaning performance or cuttings volume removal monitoring, will be based on real-time measurements of the cuttings volume removal from downhole at certain time, taking into account Flowrate, RPM, ROP and Drilling fluid or Mud properties, and then will be plotted and compared to the volume being drilled expected. ECD monitoring will dictate hole stability conditions and T&D and Cuttings Volume coming from downhole monitoring will dictate how clean the well is. T&D Modeling Software provide theoretical calculated T&D trends which will be plotted and compared to the real-time measurements. It will use the measured hookloads to perform a back-calculation of friction factors along the wellbore.