Aspectos gerais da tectónica alpina no Algarve

The study of the tectonic strutures affecting the mesozoic and cenozoic deposits of Algarve's basin allows us to recognize the following phases of the Alpine orogeny: Jurassic (Upper Triassic at least)-Lower Cretaceous N-S distension; N-S compression during the setting-up of the Monchique syenite dome at the uppermost Cretaceous; Paleogene compression (?) (only locally? - at the Albufeira salt dome); Lower Miocene N-S distension; Upper Burdigalian to Lower Langhian N-S and E-W distension; N-S or NNW-SSE compression after the Middle Miocene; E-W compression after the Upper Tortonian; N-S compression during the Quaternary. NE-SW fractures affecting the Paleozoic basement are related with the first distension phases. The mesozoic N-S distension are the main cause of the two E-W flexures so far recognized. A tectonic inversion event did occur after the setting up of the Monchique syenite. If, the Lower Cretaceous Lower Miocene Albufeira's unconformity, is a local effect of halokinesis then, the true tectonic inversion of the Algarve basin, did occur in the Middle Miocene. These events correlate well with those knewn at Southern Spain and Morocco.

Tectónica da região de Sintra

Photo-interpretation of aerial stereopairs of the Sintra region on the approx. 1/32 000 scale together with field work allowed the production of the present Tectonic Map of the Sintra region. It is now possible to separate structures which resulted from two different tectonic events: one, corresponding to the intrusion of the Late Cretaceous Sintra igneous diapir, and the other the Miocene compressive event, the most important tectonic inversion phase of the Lusitanian Basin. The former are present to the south, southeast and east of the intrusion and within the intrusion itself, affecting the peripheral granites and their contacts with the gabbro-syenite core. These structures comprehend: i) faults and conical fractures striking parallel to the massif boundary, which were intruded by dykes, ii) vertical faults and fractures of two conjugate sets, dextral NNW-SSE and sinistral NNE-SSW. These faults are certainly associated with the E-W striking massif's northwards directed thrust and indicate a N-S oriented horizontal maximum compressive stress. The Miocene compressive event reactivated most of the inherited structures as follows. The NNWSSE faults located on the Sintra southern platform were reactivated as dextral strike slip faults and the E-W thrust along the northern boundary of the massif was also reactivated. This thrust propagated to the east. It also enhanced the asymmetry of the rim-syncline, uplifted the massif and reactivated the NNE-SSW faults as sinistral lateral ramps, which also accommodated vertical throw. The present Tectonic Map of Sintra together with the available geophysical data (MOREIRA, 1984, KULLBERG et al., 1991, SILVA & MIRANDA, 1994) allowed reassessment of the models proposed for the emplacement of the Sintra, Sines and Monchique igneous massifs, which intruded during Late Cretaceous times along the deep dextral NNW-SSE oriented strike slip fault (RIBEIRO et al., 1979; TERRINHA, 1998; TERRINHA & KULLBERG, 1998).

Interpretação tectónica de um conjunto de lineamentos WNW-ESE observados em imagens landsat da margem oeste ibérica

The existence of satellite images ofthe West Iberian Margin allowed comparative study of images as a tool applied to structural geology. Interpretation of LANDSAT images of the Lusitanian Basin domain showed the existence of a not previously described WNW-ESE trending set oflineaments. These lineaments are persistent and only observable on small scale images (e.g. approx. 11200000 and 11500 000) with various radiometric characteristics. They are approximately 20 km long, trend l200±15° and cross cut any other families oflineaments. The fact that these lineaments are perpendicular to the Quaternary thrusts of the Lower Tagus Valley and also because they show no off-set across them, suggests that they resulted from intersection oflarge tensile fractures on the earth's surface. It is proposed in this work that these lineaments formed on a crustal flexure of tens ofkm long, associated with the Quaternary WNW-ESE oriented maximum compressive stress on the West Iberian Margin. The maximum compressive stress rotated anticlockwise from a NW -SE orientation to approximately WNW-ESE, from Late Miocene to Quaternary times (RIBEIRO et aI., 1996). Field inspection of the lineaments revealed zones of norm~1.J. faulting and cataclasis, which are coincident with the lineaments and affect sediments of upper Miocene up to Quaternary age. These deformation structures show localized extension perpendicular to the lineaments, i.e. perpendicular to the maximum compressive direction, after recent stress data along the West Portuguese Margin (CABRAL & RIBEIRO, 1989; RIBEIRO et at., 1996). Also, on a first approach, the geographical distribution of these lineaments correlates well with earthquake epicenters and areas of largest Quaternary Vertical Movements within the inverted Lusitanian Basin (CABRAL, 1995).

Measurement of lead concentration in biological tissues by atomic spectroscopy techniques

Dissertation for the degree of Doctor of Philosophy in Physics

Osteoporosis in Paediatric Patients with Spina Bifida

The prevalence andmorbidity associated with osteoporosis and fractures in patients with spina bifida (SB) highlight the importance of osteoporosis prevention and treatment in early childhood; however, the issue has received little attention. The method for the selection of appropriate patients for drug treatment has not been clarified. Objective: To review the literature concerning fracture risks and low bone density in paediatric patients with SB. We looked for studies describing state-of-the-art treatments and for prevention of secondary osteoporosis. Methods: Articles were identified through a search in the electronic database (PUBMED) supplemented with reviews of the reference lists of selected papers. The main outcome measures were incidence of fractures and risk factors for fracture, an association between bone mineral density (BMD) and occurrence of fracture, risk factors of low BMD, and effects of pharmacological and non-pharmacological treatments on BMD and on the incidence of fractures. We considered as a secondary outcome the occurrence of fractures in relation to the mechanism of injury. Results: Results indicated that patients with SB are at increased risk for fractures and low BMD. Risk factors that may predispose patients to fractures include higher levels of neurological involvement, non-ambulatory status, physical inactivity, hypercalciuria, higher body fat levels, contractures, and a previous spontaneous fracture. Limitations were observed in the number and quality of studies concerning osteoporosis prevention and treatment in paediatric patients with SB. The safety and efficiency of drugs to treat osteoporosis in adults have not been evaluated satisfactorily in children with SB.

Mid-Term Results of EVAR in Severe Proximal Aneurysm Neck Angulation.

OBJECTIVE: To determine if mid-term outcome following endovascular aneurysm repair (EVAR) with the Endurant Stent Graft (Medtronic, Santa Rosa, CA, USA) is influenced by severe proximal neck angulation. METHODS: A retrospective case-control study was performed using data from a prospective multicenter database. All measurements were obtained using dedicated reconstruction software and center-lumen line reconstruction. Patients with neck length >15 mm, infrarenal angle (β) >75°, and/or suprarenal angle (α) >60°, or neck length >10 mm with β >60°, and/or α >45° were compared with a matched control group. Primary endpoint was primary clinical success. Secondary endpoints were freedom from rupture, type 1A endoleak, stent fractures, freedom from neck-related reinterventions, and aneurysm-related adverse events. Morphological neck variation over time was also assessed. RESULTS: Forty-five patients were included in the study group and were compared with a matched control group with 65 patients. Median follow-up time was 49.5 months (range 30.5-58.4). The 4-year primary clinical success estimates were 83% and 80% for the angulated and nonangulated groups (p = .42). Proximal neck angulation did not affect primary clinical success in a multivariate model (hazard ratio 1.56, 95% confidence interval 0.55-4.41). Groups did not differ significantly in regard to freedom from rupture (p = .79), freedom from type 1A endoleak (p = .79), freedom from neck-related adverse events (p = .68), and neck-related reinterventions (p = .68). Neck angle reduction was more pronounced in patients with severe proximal neck angulation (mean Δα -15.6°, mean Δβ -30.6°) than in the control group (mean Δα -0.39°, mean Δβ -5.9°) (p < .001). CONCLUSION: Mid-term outcomes following EVAR with the Endurant Stent Graft were not influenced by severe proximal neck angulation in our population. Despite the conformability of the device, moderate aortic neck remodeling was identified in the group of patients with angulated neck anatomy on the first computed tomography scan after implantation with no important further remodeling afterwards. No device integrity failures were encountered.

Thermo-hydro-mechanical analysis of CO2 injection into deep aquifers

One of the biggest challenges for humanity is global warming and consequently, climate changes. Even though there has been increasing public awareness and investments from numerous countries concerning renewable energies, fossil fuels are and will continue to be in the near future, the main source of energy. Carbon capture and storage (CCS) is believed to be a serious measure to mitigate CO2 concentration. CCS briefly consists of capturing CO2 from the atmosphere or stationary emission sources and transporting and storing it via mineral carbonation, in oceans or geological media. The latter is referred to as carbon capture and geological storage (CCGS) and is considered to be the most promising of all solutions. Generally it consists of a storage (e.g. depleted oil reservoirs and deep saline aquifers) and sealing (commonly termed caprock in the oil industry) formations. The present study concerns the injection of CO2 into deep aquifers and regardless injection conditions, temperature gradients between carbon dioxide and the storage formation are likely to occur. Should the CO2 temperature be lower than the storage formation, a contractive behaviour of the reservoir and caprock is expected. The latter can result in the opening of new paths or re-opening of fractures, favouring leakage and compromising the CCGS project. During CO2 injection, coupled thermo-hydro-mechanical phenomena occur, which due to their complexity, hamper the assessment of each relative influence. For this purpose, several analyses were carried out in order to evaluate their influences but focusing on the thermal contractive behaviour. It was finally concluded that depending on mechanical and thermal properties of the pair aquifer-seal, the sealing caprock can undergo significant decreases in effective stress.

Estimação da permeabilidade em reservatórios fraturados - Comparação entre o método do tensor e o método de upscaling

A simulação dinâmica de reservatórios de petróleo requer a alocação de permeabilidades equivalentes para todos os blocos. A determinação da permeabilidade equivalente em reservatórios fraturados é uma questão complexa e crítica no fluxograma de modelação, porque é totalmente dependente da geometria 3D sistema de fraturas, e respetivas aberturas, que muitas vezes são mal conhecidos. Para avaliar a permeabilidade equivalente de blocos fraturados, o método do tensor ou de Oda é um dos mais utilizados. É expedito e eficiente mesmo para a sistemas com vários milhões de fraturas. Todavia, na literatura são apontadas algumas críticas, por exemplo, sobrestima a permeabilidade em blocos pouco fraturados e subestima-a em blocos muito fraturados. Este trabalho tem como objetivos, revisitar a problemática da caracterização da permeabilidade equivalente em blocos de reservatórios fraturados. Recorreu-se a um pacote de programas informáticos FROM3D-K (fractures object model – permeability evaluation) desenvolvidos e/ ou adaptados no contexto deste trabalho e que permitem as funcionalidades: (1) simulação estocástica 3D de fraturas; (2) determinação da permeabilidade equivalente pelo método do tensor; (3) determinação da permeabilidade equivalente pelo método de upscaling de microblocos. Estas funções permitem que a mesma rede de fraturas seja avaliada pelos dois métodos. Para a demonstração de resultados mostram-se dois exemplos, o primeiro onde são simuladas fraturas condicionadas a estatísticas sintéticas de orientação, intensidade e abertura e o segundo onde se utilizam dados FMI de poço de um reservatório fraturado.

Intervenção da fisiopetarpia em indivíduos com osteoartrose do joelho: características da prática clínica e resultados obtidos em contexto de prática convencionada

RESUMO: Introdução: A osteoartrose do joelho em particular constitui uma das maiores causas de incapacidades no dia-a-dia, morbilidade e aumento dos custos de saúde na população, na medida em que é uma condição que quando sintomática progride para um padrão que incluí dor articular, perda de força, incapacidade para a marcha e redução da aptidão física. A sua prevalência aumenta com a idade, 7% entre pessoas dos 65-70 anos, e 11,2% para aqueles com 80 anos ou mais, pouco variando entre os estudos existentes. Um recente estudo da Organização Mundial da Saúde (OMS) refere que a osteoartrose é a quarta causa mais importante de incapacidade entre as mulheres e a oitava entre os homens. Objetivo do estudo: Descrever a intervenção da fisioterapia em contexto de prática clínica convencionada e os resultados obtidos em indivíduos com OA, ao nível da intensidade da dor, capacidade funcional e perceção global de melhoria. Desenho Metodológico: Trata-se de um Estudo de coorte prospetivo onde foram incluídos indivíduos de ambos os géneros, entre os 60 e os 80 anos, com osteoartrose do joelho referenciada clinicamente. Após o consentimento informado, os pacientes foram, avaliados em quatro momentos: num primeiro momento (T0), antes de iniciarem o tratamento; (T1) após 4 semanas do início do tratamento; (T2) coincidente com o final do tratamento; e (T3) 3 meses após o início do tratamento. Foi utilizado um Questionário de Caracterização Sócio-Demográfica e Clínica, a Escala numérica da dor – END, o questionário KOOS (Knee Injury and Osteoarthritis Outcome Score) e a versão portuguesa da Patient Global Impression Change (PGIC-PT). A base de seleção dos indivíduos foi realizada numa clínica convencionada do Algarve. Resultados: Foi observado um aumento significativo em todos os outcomes avaliados pelo KOOS, END e PGIC num período até 3 meses após a intervenção. Na avaliação da END em T3 o valor da média foi de 1,63(±0,71). Para o KOOS nas subescalas Sintomas foi de 87,60(±5,86), Dor 85,71(±3,99), AVD 78,23(±3,48), ADL 67,71(±7,16), QV 80,71(±9,14), para a PGIC-AVD 5,29(±0,57), PGIC-DOR 5,97(±0,61). Os resultados obtidos pelo teste de Friedman, revelaram um valor de p<0,005. Assim, a melhoria da incapacidade funcional reportada pelos participantes neste grupo é estatisticamente diferente, e de forma significativa nos diferentes momentos de recolha de dados, durante e após o tratamento (X2 (3)=208,862, p<0,005)/ (X2(3)=205,041, p<0,005). Por fim os valores do somatório dos participantes, que estão inseridos em no grupo dos “Bons Resultados”( ≥5) foi de 27,14% em T0 passando para 100,00% em T3, enquanto que o grupo dos “Maus Resultados”(<5) foi de 72,86% em T0 e 100% em T3. Conclusão: Os resultados do presente estudo sugerem que a intervenção da Fisioterapia efetuadas em clínicas convencionadas nos casos da Osteoartrose do joelho são efetivas na redução significativa dos níveis de dor e incapacidade funcional e na Perceção global de melhoria em pacientes com Osteoartrose do joelho. ---------- ABSTRACT: Introduction: Osteoarthritis of the knee in particular is a major cause of disabilities in their day-to-day morbidity and increased healthcare costs in the population, in that it is a disease that when symptomatic progresses to a pattern that included joint pain, strength loss, inability to walk and reduction of physical fitness. It is referred as a risk factor for falls and fractures. Its prevalence increases with age, 7% of people between 65-70 years, and 11.2% for those aged 80 or more, ranging from some existing studies. A recent study by the World Health Organization (WHO) reports that osteoarthritis is the fourth leading cause of disability among women and eighth among men. Objective: To describe the characteristics and the outcomes of the physiotherapy practice in patients with knee osteoarthritis. Methodology: A prospective cohort study, with 70 individuals, aged between 60 and 80 years with the diagnosis of knee osteoarthritis and referred to physiotherapy treatment, was carried out. After informed consent, patients were evaluated in four different moments: at baseline (T0), before starting treatment; 4 weeks after starting their treatment (T1); 8 weeks after starting their treatment (T2); and in a 3 months follow-up (T3). Patients were assessed for their socio-demographic and clinical characteristics, pain intensity (using the numeric pain rating scale- NRS), disability (using the Knee Injury and Osteoarthritis Outcome Score), and for their global impression of change (using the Portuguese version of the Patient Glogal Impression of Change scale). Results: The findings of this study indicate a significant increase in all outcomes assessed (pain, disability and global impression of change), during and after the physiotherapy treatment. At T3, the average value for the NRS was 1.63 (± 0.71). For KOOS in the symptoms subscales was 87.60 (± 5.86), pain 85.71 (± 3.99), ADL 78.23 (± 3.48), ADL 67.71 (± 7.16), QV 80.71 (± 9.14) for the PGIC-AVD 5.29 (± 0.57), PGIC-PAIN 5.97 (± 0.61). The results obtained though the Friedman test revealed a p-value <0.005. Thus, the improvement of functional capacity reported by participants in the group was statistically different at the different moments of data collection, during and after treatment (X 2 (3) = 208.862, p <0.005) / (X 2 (3) = 205.041, p <0.005). Conclusion: The results of this study show that the physiotherapy treatments made on agreed clinics in cases of osteoarthritis of the knee, are effective in significant reduction in the levels of pain and disability and in perception of overall improvement perception in patients with osteoarthritis of the Knee.

Essays in health economics: Volume-Outcome Effect, upcoding behaviour and the evaluation of a short-term intervention program

Evidence in the literature suggests a negative relationship between volume of medical procedures and mortality rates in the health care sector. In general, high-volume hospitals appear to achieve lower mortality rates, although considerable variation exists. However, most studies focus on US hospitals, which face different incentives than hospitals in a National Health Service (NHS). In order to add to the literature, this study aims to understand what happens in a NHS. Results reveal a statistically significant correlation between volume of procedures and better outcomes for the following medical procedures: cerebral infarction, respiratory infections, circulatory disorders with AMI, bowel procedures, cirrhosis, and hip and femur procedures. The effect is explained with the practice-makes-perfect hypothesis through static effects of scale with little evidence of learning-by-doing. The centralization of those medical procedures is recommended given that this policy would save a considerable number of lives (reduction of 12% in deaths for cerebral infarction).

Experimental determination of bone cortex holding power of orthopedic screw

Cylindrical specimens of bone measuring 15 mm in diameter were obtained from the lateral cortical layer of 10 pairs of femurs and tibias. A central hole 3.2 mm in diameter was drilled in each specimen. The hole was tapped, and a 4.5 mm cortical bone screw was inserted from the outer surface. The montage was submitted to push-out testing up to a complete strip of the bone threads. The cortical thickness and rupture load were measured, and the shear stress was calculated. The results were grouped according to the bone segment from which the specimen was obtained. The results showed that bone cortex screw holding power is dependent on the bone site. Additionally, the diaphyseal cortical bone tissue is both quantitatively and qualitatively more resistant to screw extraction than the metaphyseal tissue.

Normal bone density in male pseudohermaphroditism due to 5alpha- reductase 2 deficiency

Bone is an androgen-dependent tissue, but it is not clear whether the androgen action in bone depends on testosterone or on dihydrotestosterone. Patients with 5alpha-reductase 2 deficiency present normal levels of testosterone and low levels of dihydrotestosterone, providing an in vivo human model for the analysis of the effect of testosterone on bone. OBJECTIVE: To analyze bone mineral density in 4 adult patients with male pseudohermaphroditism due to 5alpha-reductase 2 deficiency. RESULTS: Three patients presented normal bone mineral density of the lumbar column (L1-L4) and femur neck, and the other patient presented a slight osteopenia in the lumbar column. CONCLUSION: Patients with dihydrotestosterone deficiency present normal bone mineral density, suggesting that dihydrotestosterone is not the main androgen acting in bone.

Bone turnover markers for early detection of fracture healing disturbances: A review of the scientific literature

Imaging techniques are the standard method for assessment of fracture healing processes. However, these methods are perhaps not entirely reliable for early detection of complications, the most frequent of these being delayed union and non-union. A prompt diagnosis of such disorders could prevent prolonged patient distress and disability. Efforts should be directed towards the development of new technologies for improving accuracy in diagnosing complications following bone fractures. The variation in the levels of bone turnover markers (BTMs) have been assessed with regard to there ability to predict impaired fracture healing at an early stage, nevertheless the conclusions of some studies are not consensual. In this article the authors have revised the potential of BTMs as early predictors of prognosis in adult patients presenting traumatic bone fractures but who did not suffer from osteopenia or postmenopausal osteoporosis. The available information from the different studies performed in this field was systematized in order to highlight the most promising BTMs for the assessment of fracture healing outcome.

Influence of the hip joint modeling approaches on the kinematics of human gait

The influence of the hip joint formulation on the kinematic response of the model of human gait is investigated throughout this work. To accomplish this goal, the fundamental issues of the modeling process of a planar hip joint under the framework of multibody systems are revisited. In particular, the formulations for the ideal, dry, and lubricated revolute joints are described and utilized for the interaction of femur head inside acetabulum or the hip bone. In this process, the main kinematic and dynamic aspects of hip joints are analyzed. In a simple manner, the forces that are generated during human gait, for both dry and lubricated hip joint models, are computed in terms of the system’s state variables and subsequently introduced into the dynamics equations of motion of the multibody system as external generalized forces. Moreover, a human multibody model is considered, which incorporates the different approaches for the hip articulation, namely ideal joint, dry, and lubricated models. Finally, several computational simulations based on different approaches are performed, and the main results presented and compared to identify differences among the methodologies and procedures adopted in this work. The input conditions to the models correspond to the experimental data capture from an adult male during normal gait. In general, the obtained results in terms of positions do not differ significantly when the different hip joint models are considered. In sharp contrast, the velocity and acceleration plotted vary significantly. The effect of the hip joint modeling approach is clearly measurable and visible in terms of peaks and oscillations of the velocities and accelerations. In general, with the dry hip model, intra-joint force peaks can be observed, which can be associated with the multiple impacts between the femur head and the cup. In turn, when the lubricant is present, the system’s response tends to be smoother due to the damping effects of the synovial fluid.

A 3D computer assisted Orthopedic Surgery Planning approach based on planar radiography

Dissertação de mestrado integrado em Engenharia Biomédica (área de especialização em Informática Médica)