404 research outputs found

    BENDING THE DOMING EFFECT IN STRUCTURE FROM MOTION RECONSTRUCTIONS THROUGH BUNDLE ADJUSTMENT

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    Structure from Motion techniques provides low-cost and flexible methods that can be adopted in arial surveying to collect topographic data with accurate results. Nevertheless, the so-called "doming effect", due to unfortunate acquisition conditions or unreliable modeling of radial distortion, has been recognized as a critical issue that disrupts the quality of the attained 3D reconstruction. In this paper we propose a novel method, that works effectively in the presence of a nearly flat soil, to tackle a posteriori the doming effect: an automatic ground detection method is used to capture the doming deformation flawing the reconstruction, which in turn is wrapped to the correct geometry by iteratively enforcing a planarity constraint through a Bundle Adjustment framework. Experiments on real word datasets demonstrate promising results

    BENDING THE DOMING EFFECT IN STRUCTURE FROM MOTION RECONSTRUCTIONS THROUGH BUNDLE ADJUSTMENT

    Get PDF
    Structure from Motion techniques provides low-cost and flexible methods that can be adopted in arial surveying to collect topographic data with accurate results. Nevertheless, the so-called “doming effect”, due to unfortunate acquisition conditions or unreliable modeling of radial distortion, has been recognized as a critical issue that disrupts the quality of the attained 3D reconstruction. In this paper we propose a novel method, that works effectively in the presence of a nearly flat soil, to tackle a posteriori the doming effect: an automatic ground detection method is used to capture the doming deformation flawing the reconstruction, which in turn is wrapped to the correct geometry by iteratively enforcing a planarity constraint through a Bundle Adjustment framework. Experiments on real word datasets demonstrate promising results

    Numerical simulation of extreme wave runup during storm events in Tramandaí­ Beach, Rio Grande do Sul, Brazil

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    We present a high resolution analysis of the interaction of irregular waves with natural and urban structures leading to extreme wave runup. Horizontal runup data, instantaneous flooding maps, and wave propagation beyond the coastline are numerically predicted. The novel methodology combining the Wave Watch III, SWAN and SWASH models to achieve accurate and computationally feasible simulation of waves at different time and spatial scales, from the formation process at deep water up to the total energy dissipation in the swash zone, is proposed. An access to the LIDAR database has provided a high resolution (15. cm-25. cm) of the subaerial surface which is essential for accurate representation of the hydrodynamic interactions with the beach profile. The suggested approach has been applied for evaluation of wave runup related to six storm events in Tramandaí Beach in Southern Brazil. This allowed for an identification of critical vulnerable overwashing areas as well as, critical information on flooding zones. The results are in agreement with the runup measurements performed in January 2014. The numerical methodology employed in this work has been also compared with the survey and conventional empirical model data. It was discovered that the empirical models lead to the systematic overestimation of the runup results

    Dietary Fat, Sugar Consumption, and Cardiorespiratory Fitness in Patients With Heart Failure With Preserved Ejection Fraction

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    Heart failure with preserved ejection fraction (HFpEF) is associated with obesity and, indirectly, with unhealthy diet. The role of dietary components in HFpEF is, however, largely unknown. In this study, the authors showed that in obese HFpEF patients, consumption of unsaturated fatty acids (UFA), was associated with better cardiorespiratory fitness, and UFA consumption correlated with better diastolic function and with greater fat-free mass. Similarly, mice fed with a high-fat diet rich in UFA and low in sugars had preserved myocardial function and reduced weight gain. Randomized clinical trials increasing dietary UFA consumption and reducing sugar consumption are warranted to confirm and expand our findings

    Sedimentação da Lagoa Itapeva, RS, Brasil

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    Hydrodynamic factors that control sedimentation in the Itapeva Lake were assessed on the granulometric distribution map generated by the Pejrup’s diagram and by the analysis of the hydrodynamic action, which results from the waves in the lacustrine body. The texture patterns of bottom samples showed that there is significant hydrodynamic energy in the sedimentation process: the sand fraction prevails in the submerged margins whereas grain size decreases, from coarse silt to fine silt, moved towards the center. The content of organic matter also shows this pattern, with a steady increase in the central area of the lacustrine body and near the mouths of the Três Forquilhas and Cardoso rivers. The main processes that determine sedimentation are mainly controlled by the amount of fluvial sediment, which is redistributed by the action of waves and currents resulting from the action of winds. The concentration of clay-sized grains is not very significant not only because there is low input by the rivers, but also because the wave agitation avoid this granulometric class from depositing on the lacustrine bottom. Fine sediment in the deepest spots and in the most sheltered areas shows the influence of less effective currents that enable deposition in these areas.Os fatores hidrodinâmicos que controlam a sedimentação na Lagoa Itapeva foram avaliados através do mapa de distribuição granulométrica gerado a partir do diagrama de Pejrup e da análise da ação hidrodinâmica induzida pelas ondas no corpo lacustre. Os padrões texturais das amostras de fundo indicaram a presença de significativa energia hidrodinâmica atuante no processo de sedimentação, com predomínio da fração arenosa nas margens submersas e granodecrescência para tamanhos silte grosso a fino em direção ao centro. O teor de matéria orgânica também apresenta este padrão, com aumento gradativo na área central do corpo lacustre e nas proximidades das desembocaduras dos rios Três Forquilhas e Cardoso. Os principais processos que condicionam a sedimentação na lagoa são controlados pelo aporte de sedimentos fluviais, redistribuídos pela ação das ondas e correntes induzidas pela ação dos ventos. A concentração de grãos tamanho argila é pouco significativa, devido à baixa inserção pelos rios, além da agitação gerada por ondas sobre o piso lacustre, que dificulta a deposição desta classe granulométrica. A presença de sedimentos finos nos locais mais profundos e nas áreas mais abrigadas indica a influência de correntes menos efetivas, permitindo a deposição nestes locais

    O Controle da Deriva Litorânea no Desenvolvimento do Campo de Dunas e da Antepraia no Litoral Médio do Rio Grande do Sul

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    Zones of erosion and accretion were delimited by comparing a DGPS shoreline mapping in 1997 and the beach line reproduced from the army chart collection of 1975. The results show extensive shore retreat along of Rio Grande do Sul central coast, while accretion was observed in Mostardas and Dunas Altas beach. Mathematical estimative of the regional longshore transport potential along the Rio Grande do Sul coast, a 630-km long holocenic fine sand barrier, resulted in a large net northward annual sand volume. Additionally, the estimated potential of sediment transport based on the CERC formula predicts a substantial variation of the energy flux into the surf zone, due to little changes in shoreline alignments and in the potential alongshore sediment transport. The reduction in the sediment flux due to changes in the shoreline alignment produce a jam in the longshore transport, meaning that part of the sediment arriving from the upstream stretch may be deposited or diverted offshore by coastal jet. Based on that, it is possible that changes in the net longshore sand transport are responsible for the increase in the shoreface width from less than 1 km to more than 3 km in Mostardas beach and Dunas Altas beach. Interesting to note that wider dune fields are associated to those beaches where shoreface is also wider. In this way, the volume of longshore sand transport and the sediment jam provide by changes on shoreline alignment in Mostardas and Dunas Altas beaches are important for both coastal dune fields and shoreface width.Zones of erosion and accretion were delimited by comparing a DGPS shoreline mapping in 1997 and the beach line reproduced from the army chart collection of 1975. The results show extensive shore retreat along of Rio Grande do Sul central coast, while accretion was observed in Mostardas and Dunas Altas beach. Mathematical estimative of the regional longshore transport potential along the Rio Grande do Sul coast, a 630-km long holocenic fine sand barrier, resulted in a large net northward annual sand volume. Additionally, the estimated potential of sediment transport based on the CERC formula predicts a substantial variation of the energy flux into the surf zone, due to little changes in shoreline alignments and in the potential alongshore sediment transport. The reduction in the sediment flux due to changes in the shoreline alignment produce a jam in the longshore transport, meaning that part of the sediment arriving from the upstream stretch may be deposited or diverted offshore by coastal jet. Based on that, it is possible that changes in the net longshore sand transport are responsible for the increase in the shoreface width from less than 1 km to more than 3 km in Mostardas beach and Dunas Altas beach. Interesting to note that wider dune fields are associated to those beaches where shoreface is also wider. In this way, the volume of longshore sand transport and the sediment jam provide by changes on shoreline alignment in Mostardas and Dunas Altas beaches are important for both coastal dune fields and shoreface width

    Geocronologia com 210Pb na avaliação das taxas de sedimentação e da dinâmica deposicional na Lagoa Itapeva, sul do Brasil

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    As a result of anthropogenic activities, coastal lakes are potentially threatened by increased sedimentation rates and relative sea-level increases. The present study analyzed the sedimentary-filling conditions of Itapeva Lake by using the 210Pb geochronology method, which is based on 210Pb and 226Ra activity values obtained from three sediment cores. Measurements of sedimentation rates in the core C3 indicate a strong influence of the drainage of the Três Forquilhas River with values of approximately 3.2 mm.a-1. The sampling points in the center (C2) and north (C1) exhibited significantly lower values of 2.4 and 2.9 mm.a-1, respectively. These values are lower than the rates of relative sea-level increase, which indicate a transitional scenario between the stabilization and sedimentary deficit in the lacustrine burial process. The particle size analysis in the core samples indicates the presence of significant hydrodynamic energy in the sedimentation. The silt fraction is the dominant class, with variations in size ranging from medium to coarse in all samples, followed by the occurrence of fraction sand in relation to clay which presented low concentration, not over 9%. However, an increase in mud content has been observed in the core C3 over the last several decades, which suggests changes in the drainage basin of the Três Forquilhas River due to an increase in sediment production. Urbanization and the introduction of agriculture within the last century are the main reasons for this behaviorLagoas costeiras são ambientes potencialmente ameaçados pelo aumento recente das taxas de sedimentação e elevação relativa do nível do mar. Neste trabalho foram analisadas as condições de preenchimento sedimentar da Lagoa Itapeva utilizando o método geocronológico 210Pb, a partir dos valores da atividade do 210Pb e 226Ra obtidos de três testemunhos geológicos. As taxas de sedimentação medidas no testemunho C3 indicam forte influência da drenagem do Rio Três Forquilhas, com valores na ordem de 3,2 mm.a-1. Os pontos de coleta no centro C2 e norte C1 apresentaram valores sensivelmente menores, 2,4 e 2,9 mm.a-1, respectivamente. Tais valores mostram-se inferiores as taxas de elevação relativa do nível do mar, indicando um cenário transicional entre a estabilização e o déficit sedimentar no processo de preenchimento lacustre. A análise granulométrica nos testemunhos indica a presença de significativa energia hidrodinâmica no processo de sedimentação. A fração silte é a classe dominante, com variação entre o tamanho médio a grosso em todas as amostras, seguida pela ocorrência da fração areia em relação à argila que apresentou baixa concentração, não ultrapassando 9%. Entretanto, foi verificado no testemunho C3 um aumento do teor de lamas nas últimas décadas, o que sugere modificações na bacia de drenagem do Rio Três Forquilhas pelo aumento na produção de sedimentos. A urbanização e a introdução da agricultura no último século são as principais variáveis que explicam este comportamento

    neuroimaging changes in menkes disease part 2

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    SUMMARY: This is the second part of a retrospective and review MR imaging study aiming to define the frequency rate, timing, imaging features, and evolution of gray matter changes in Menkes disease, a rare multisystem X-linked disorder of copper metabolism characterized by early, severe, and progressive neurologic involvement. According to our analysis, neurodegenerative changes and focal basal ganglia lesions already appear in the early phases of the disease. Subdural collections are less common than generally thought; however, their presence remains important because they might challenge the differential diagnosis with child abuse and might precipitate the clinical deterioration. Anecdotal findings in our large sample seem to provide interesting clues about the protean mechanisms of brain injury in this rare disease and further highlight the broad spectrum of MR imaging findings that might be expected while imaging a child with the suspicion of or a known diagnosis of Menkes disease

    Headache attributed to aeroplane travel: the first multicentric survey in a paediatric population affected by primary headaches

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    BACKGROUND: This multicentric survey investigates the prevalence and characteristics of Airplane Headache in children affected by primary headaches. METHODS: Patients with symptoms of Airplane Headache were recruited from nine Italian Pediatric Headache Centres. Each patient was handed a structured questionnaire which met the ICHD-III criteria. RESULTS: Among 320 children suffering from primary headaches who had flights during their lifetime, 15 (4.7%) had Airplane Headache, with mean age of 12.4 years. Most of the patients were females (80%). The headache was predominantly bilateral (80%) and localized to the frontal area (60%); it was mainly pulsating, and lasted less than 30 min in all cases. Accompanying symptoms were tearing, photophobia, phonophobia in most of the cases (73.3%). More than 30% of patients used medications to treat the attacks, with good results. CONCLUSION: Our study shows that Airplane Headache is not a rare disorder in children affected by primary headaches and highlights that its features in children are peculiar and differ from those described in adults. In children Airplane Headache prevails in females, is more often bilateral, has frequently accompanying symptoms and occurs at any time during the flight. Further studies are needed to confirm the actual frequency of Airplane Headache in the general pediatric population not selected from specialized Headache Centres, with and without other concomitant headache condition, and to better clarify the clinical characteristics, pathophysiology and potential therapies
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