Geohazard assessment of landslides in south Brazil: Case study

Slope instability phenomena such as mudslides represent a major geohazard in Brazil, which has caused devastation in many states and affected the lives of people, particularly in self-built settlements on steep slopes. This paper presents and discusses slope stability issues encountered in Caxias do Sul in the State of Rio Grande do Sul, which exemplifies the existing situation of landslide risk assessment in southern Brazil. Local geology and ground conditions of the area in relation to slope instability were reviewed and gaps in information required for mitigating risk were identified, such as inadequate geotechnical information and lack of full inspection and continuous monitoring of active landslides. Although risk assessment has been developed for the city and regarded as a fundamental management tool in the mitigation of landslide hazards, the study showed that the risk assessment works are outdated and not effectively considered for the development of the city. With significant unplanned urban expansion (where houses have been self-built on very steep terrains without geotechnical assessment of the ground and slope conditions), new geohazard mapping is essentially required. Several key recommendations were provided for mitigating the destructive effect of landslides and improving their management in mountainous urban settings.Newton Researcher Links (Ref. NRCP1617/6/182) administrated by the Royal Academy of Engineering (RAEng)

Incidence of Esophageal Thermal Injury Using a Safety Protocol During Atrial Fibrillation Ablation

Objective: Catheter ablation has been a common procedure used for the management of atrial fibrillation (AF). Atrioesophagel fistula (AEF) is one of the most feared complications of AF ablation. Although it is a rare complication, severe esophageal thermal injury must be avoided. It is important to describe a safe method of preventing esophageal injuries without increasing AF recurrence. Methods: A retrospective cohort study of consecutive patients who underwent radiofrequency AF catheter ablation during 1 year-period wa conducted. One hundred and four patients were enrolled divided in two groups: one with a maximum recorded esophageal temperature (ET) < 38 °C and other with a maximum recorded ET ≥ 38 °C. The primary endpoint was detection of endoscopic esophageal lesions after AF ablation and the secondary endpoint was AF recurrence according to the maximum ET reached during the procedure. Results: The maximum ET was on average 37.3 ± 1.0 °C. Only 4 (3.8%) patients had esophageal lesion diagnosed by upper gastrointestinal endoscopy. There were no cases of esophageal perforation. The AF recurrence rate was 9.6% during the follow-up (10 patients, 3 from the ET max < 38 °C group and 7 from the ET max ≥ 38 °C group; p = 0.181). The maximum ET was not associated with AF recurrence after catheter ablation (OR = 1.65, 95% CI = 0.84-3.24, p = 0.14). Conclusions: A low incidence of esophageal injury after AF ablation with the use of a specific esophageal protection protocol was found. There was no esophageal perforation. The AF recurrence rate was similar to that described in the literature

Incidence of Esophageal Thermal Injury Using a Safety Protocol During Atrial Fibrillation Ablation

Objective: Catheter ablation has been a common procedure used for the management of atrial fibrillation (AF). Atrioesophagel fistula (AEF) is one of the most feared complications of AF ablation. Although it is a rare complication, severe esophageal thermal injury must be avoided. It is important to describe a safe method of preventing esophageal injuries without increasing AF recurrence. Methods: A retrospective cohort study of consecutive patients who underwent radiofrequency AF catheter ablation during 1 year-period wa conducted. One hundred and four patients were enrolled divided in two groups: one with a maximum recorded esophageal temperature (ET) < 38 °C and other with a maximum recorded ET ≥ 38 °C. The primary endpoint was detection of endoscopic esophageal lesions after AF ablation and the secondary endpoint was AF recurrence according to the maximum ET reached during the procedure. Results: The maximum ET was on average 37.3 ± 1.0 °C. Only 4 (3.8%) patients had esophageal lesion diagnosed by upper gastrointestinal endoscopy. There were no cases of esophageal perforation. The AF recurrence rate was 9.6% during the follow-up (10 patients, 3 from the ET max < 38 °C group and 7 from the ET max ≥ 38 °C group; p = 0.181). The maximum ET was not associated with AF recurrence after catheter ablation (OR = 1.65, 95% CI = 0.84-3.24, p = 0.14). Conclusions: A low incidence of esophageal injury after AF ablation with the use of a specific esophageal protection protocol was found. There was no esophageal perforation. The AF recurrence rate was similar to that described in the literature

not available

Mistura compactada de materiais inconsolidados das formações Serra Geral e Botucatu foram percoladas por soluções com diversas concentrações de K+, Cl- e Cu++, em testes de coluna, para a avaliar a potencialidade da sua utilização como liner. Na modelagem dos resultados adotaram-se resoluções analíticas e semi-analíticas (programa POLLUTE v6). Estudo complementar sobre o comportamento eletroquímico destes solos foi realizado pelos ensaios de titulação potenciométrica, capacidade de tamponamento, pH em água e KCI, CTC e análise mineralógica por difração de Raios-X e térmica diferencial. Os resultados mostraram uma forte influência das características da carga elétrica superficial do solo no comportamento competitivo dos íons.A compacted mixture of soils from Serra Geral and Botucatu formations were percolated by chemical solutions with several concentrations of K+, Cu++ e Cl-, in column tests, in order to assess the potential of this mixture as a liner-building material. In the modeling procedures for the results, analytical and semi-analytical solutions (POLLUTE v.6 software) were used. Additional studies about the electrochemical behavior of these soils were performed, using potenciometric titration, soil buffer capacity, pH in water and KCI and mineralogical assessment by X-Ray Diffraction and differential thermal analysis. The results showed a very strong influence of the soil superficial charge in the competitive ion behavior

not available

Mistura compactada de materiais inconsolidados das formações Serra Geral e Botucatu foram percoladas por soluções com diversas concentrações de K+, Cl- e Cu++, em testes de coluna, para a avaliar a potencialidade da sua utilização como liner. Na modelagem dos resultados adotaram-se resoluções analíticas e semi-analíticas (programa POLLUTE v6). Estudo complementar sobre o comportamento eletroquímico destes solos foi realizado pelos ensaios de titulação potenciométrica, capacidade de tamponamento, pH em água e KCI, CTC e análise mineralógica por difração de Raios-X e térmica diferencial. Os resultados mostraram uma forte influência das características da carga elétrica superficial do solo no comportamento competitivo dos íons.A compacted mixture of soils from Serra Geral and Botucatu formations were percolated by chemical solutions with several concentrations of K+, Cu++ e Cl-, in column tests, in order to assess the potential of this mixture as a liner-building material. In the modeling procedures for the results, analytical and semi-analytical solutions (POLLUTE v.6 software) were used. Additional studies about the electrochemical behavior of these soils were performed, using potenciometric titration, soil buffer capacity, pH in water and KCI and mineralogical assessment by X-Ray Diffraction and differential thermal analysis. The results showed a very strong influence of the soil superficial charge in the competitive ion behavior

Descrição e interpretação de testemunhos de sondagens

10