Propagação de fendas por fadiga quando sujeitas a carregamentos em Modo I ou Modo III

A propagação de fenda sob fadiga pode ser observada em vários componentes mecânicos, que podem ser feitos de chapa fina ou espessa (ou cascas) e, consequentemente, serem sujeitos a estado plano de tensão ou estado plano de deformação, respectivamente. As cargas aplicadas num corpo sólido que contém um entalhe estreito ou uma fenda aguda irão induzir uma zona de escoamento limite de material com uma dimensão que dependerá das propriedades mecânicas do material, bem como a espessura do corpo, o comprimento de fenda e a intensidade das cargas aplicadas. A propagação da fenda pode então ocorrer sob modo I, II, III ou modo misto. Esta tese apresenta as funções integrais JI, JII e JIII , que foram correlacionadas com os factores de intensidade de tensão KI, KII e KIII, para provetes CT espessos e finos. A avaliação dos valores do Integral-J foi feita para diferentes comprimentos de fenda, ao longo da frente de fenda, usando o Método dos Elementos Finitos (MEF), com nós colapsados e intermédios deslocados a ¼ do comprimento da aresta, com o objectivo de simular a singularidade na extremidade da fenda. A interacção entre os modos de abertura, corte e rasgamento é também discutida. Adicionalmente, a propagação de fenda sob o modo I e o modo III foi determinada experimentalmente, à temperatura ambiente, para um aço inoxidável austenítico Cr-Mn de alta resistência.

Basel III new capital requirements, impacts and bank behavior

For some years, researchers could not find a clear effect of capital adequacy on the risk profile of banks, as shareholders could increase the riskiness of the assets (qualitative effect), crowding-out the effect of reduced leverage (volume effect). Some shareholders might have the will to increase the riskiness of the assets, but they may lack the power to do so. Considering only ”powerful” shareholders, definitive conclusions were drawn but with constant ownership profile. In this paper I investigate whether there is a significant change in the type of shareholders in response to regulatory capital shocks and, if so, will the banking system be in the hands of more “desired” shareholders. I find that ownership profile responds to a regulatory shock, changing the risk appetite of the ruling power at the bank. I find more banks and the government in the ownership of undercapitalised banks and much less institutional shareholders and free float. I claim that these new shareholders may not the desired ones, given the objective of the regulatory change, as they are associated with a preference for more leverage. One possible explanation for this crowding-out effect is that regulators are trying to contain idiosyncratic risk (more linked to the riskiness of the assets) with a rule that contains systematic risk (capital adequacy). This has a distorting effect on ownership. Another insight can be drawn from the tests: supervisors should be aware of significant ownership movements that cause the crowding-out.

Basel III: The impact of new capital requirements on profitability of Portuguese Banks

This empirical study aims to explore the impact of increased capital ratio requirements, on the ROE of the Portuguese banking sector. The paper employs both a quantitative- and qualitative approach, with the qualitative approach as the main method of research. The method adopted to conduct the qualitative research was semi structured elite interviews with banking executives. Higher capital requirements decrease the ROE of banks in Portugal, but huge impairments charges, macroeconomic factors and increased costs of deposits are clearly the dominant reasons for the reduced levels of ROE the past years. Among the measures taken to increase capital ratios, reduction of RWAs and non-core assets have been the main focus, but the issuance of CoCos is regarded as the most expensive measure due to high interest payments. However, the CoCos will not have any effect on the ROE in the long term. It is difficult to draw any conclusions on the impact of more equity in the balance sheet on the ROE of Portuguese banks, as many banks currently don’t generate enough money to pay back on shareholders´ investments.

Avaliação da implementação da fase III da zona de emissões reduzidas de Lisboa

Os efeitos de uma qualidade do ar reduzida são sentidos principalmente em centros urbanos, como Lisboa, onde persistem situações de concentrações elevadas de dióxido de azoto (NO2) e matéria particulada (PM10), originadas pelo tráfego automóvel. Para diminuir a concentração desses poluentes foi implementada uma Zona de Emissões Reduzidas (ZER) em Lisboa, que entrou na fase III em janeiro de 2015. Avaliou-se a evolução da qualidade do ar nos últimos cinco anos em Lisboa, nomeadamente as excedências aos valores limite legais de curto prazo para NO2 e PM10, bem como a influência da meteorologia na sua ocorrência. A qualidade do ar, em geral, melhorou, registando-se a maioria das excedências no outono e inverno, em dias úteis e final da tarde e início da manhã, períodos coincidentes com a maior intensidade de tráfego rodoviário. A altura da base da inversão térmica e a velocidade do vento são mais reduzidas em dias com excedências, o que indicia um papel relevante da meteorologia. A avaliação do impacte da fase II da ZER nas excedências aos valores limite revelou que o número de excedências e a duração dos episódios de poluição diminuíram, mas mais significativamente em estações fora da ZER. Analisou-se a influência da fase III da ZER na composição da frota automóvel e nas emissões associadas de NOX e PM na Avenida da Liberdade, com base nos dados obtidos antes (2014) e depois (2015) da fase III. Verificou-se uma melhoria na frota em toda a cidade, mais acentuada na zona 2 que na zona 1. Concluiu-se que o impacte da fase III foi reduzido, principalmente na zona 1, possivelmente relacionado com a escassa fiscalização. Caso o número de veículos se tivesse mantido igual entre 2014 e 2015, teria sido possível uma redução de 23% nas emissões de NOX e de 8% nas de PM.

Validation of the IMPACT-III quality of life questionnaire in Swiss children with inflammatory bowel disease.

BACKGROUND AND AIMS: Inflammatory bowel disease (IBD) frequently manifests during childhood and adolescence. For providing and understanding a comprehensive picture of a patients' health status, health-related quality of life (HRQoL) instruments are an essential complement to clinical symptoms and functional limitations. Currently, the IMPACT-III questionnaire is one of the most frequently used disease-specific HRQoL instrument among patients with IBD. However, there is a lack of studies examining the validation and reliability of this instrument. METHODS: 146 paediatric IBD patients from the multicenter Swiss IBD paediatric cohort study database were included in the study. Medical and laboratory data were extracted from the hospital records. HRQoL data were assessed by means of standardized questionnaires filled out by the patients in a face-to-face interview. RESULTS: The original six IMPACT-III domain scales could not be replicated in the current sample. A principal component analysis with the extraction of four factor scores revealed the most robust solution. The four factors indicated good internal reliability (Cronbach's alpha=.64-.86), good concurrent validity measured by correlations with the generic KIDSCREEN-27 scales and excellent discriminant validity for the dimension of physical functioning measured by HRQoL differences for active and inactive severity groups (p<.001, d=1.04). CONCLUSIONS: This study with Swiss children with IBD indicates good validity and reliability for the IMPACT-III questionnaire. However, our findings suggest a slightly different factor structure than originally proposed. The IMPACT-III questionnaire can be recommended for its use in clinical practice. The factor structure should be further examined in other samples.

Y-90-Ibritumomab Tiuxetan (Zevalin (R)) Consolidation of First Remission In Advanced-Stage Follicular Non-Hodgkin's Lymphoma: Updated Results After a Median Follow-up of 66.2 Months From the International, Randomized, Phase III First-Line Indolent Trial (FIT) In 414 Patients

The FIT trial was conducted to evaluate the safety and efficacy of 90Y-ibritumomab tiuxetan (0.4 mCi/kg; maximum dose 32 mCi) when used as consolidation of first complete or partial remission in patients with previously untreated, advanced-stage follicular lymphoma (FL). Patients were randomly assigned to either 90Y-ibritumomab treatment (n = 207) or observation (n = 202) within 3 months (mo) of completing initial induction therapy (chemotherapy only: 86%; rituximab in combination with chemotherapy: 14%). Response status prior to randomization did not differ between the groups: 52% complete response (CR)/CR unconfirmed (CRu) to induction therapy and 48% partial response (PR) in the 90Y-ibritumomab arm vs 53% CR/CRu and 44% PR in the control arm. The primary endpoint was progression-free survival (PFS) of the intent-to-treat (ITT) population. Results from the first extended follow-up after a median of 3.5 years revealed a significant improvement in PFS from the time of randomization with 90Y-ibritumomab consolidation compared with control (36.5 vs 13.3 mo, respectively; P < 0.0001; Morschhauser et al. JCO. 2008; 26:5156-5164). Here we report a median follow-up of 66.2 mo (5.5 years). Five-year PFS was 47% in the 90Y-ibritumomab group and 29% in the control group (hazard ratio (HR) = 0.51, 95% CI 0.39-0.65; P < 0.0001). Median PFS in the 90Y-ibritumomab group was 49 mo vs 14 mo in the control group. In patients achieving a CR/CRu after induction, 5-year PFS was 57% in the 90Y-ibritumomab group, and the median had not yet been reached at 92 months, compared with a 43% 5-year PFS in the control group and a median of 31 mo (HR = 0.61, 95% CI 0.42-0.89). For patients in PR after induction, the 5-year PFS was 38% in the 90Y-ibritumomab group with a median PFS of 30 mo vs 14% in the control group with a median PFS of 6 mo (HR = 0.38, 95% CI 0.27-0.53). Patients who had received rituximab as part of induction treatment had a 5-year PFS of 64% in the 90Y-ibritumomab group and 48% in the control group (HR = 0.66, 95% CI 0.30-1.47). For all patients, time to next treatment (as calculated from the date of randomization) differed significantly between both groups; median not reached at 99 mo in the 90Y-ibritumomab group vs 35 mo in the control group (P < 0.0001). The majority of patients received rituximab-containing regimens when treated after progression (63/82 [77%] in the 90Y-ibritumomab group and 102/122 [84%] in the control group). Overall response rate to second-line treatment was 79% in the 90Y-ibritumomab group (57% CR/CRu and 22% PR) vs 78% in the control arm (59% CR/CRu, 19% PR). Five-year overall survival was not significantly different between the groups; 93% and 89% in the 90Y-ibritumomab and control groups, respectively (P = 0.561). To date, 40 patients have died; 18 in the 90Y-ibritumomab group and 22 in the control group. Secondary malignancies were diagnosed in 16 patients in the 90Y-ibritumomab arm vs 9 patients in the control arm (P = 0.19). There were 6 (3%) cases of myelodysplastic syndrome (MDS)/acute myelogenous leukemia (AML) in the 90Y-ibritumomab arm vs 1 MDS in the control arm (P = 0.063). In conclusion, this extended follow-up of the FIT trial confirms the benefit of 90Y-ibritumomab consolidation with a nearly 3 year advantage in median PFS. A significant 5-year PFS improvement was confirmed for patients with a CR/CRu or a PR after induction. Effective rescue treatment with rituximab-containing regimens may explain the observed no difference in overall survival between both patient groups who were - for the greater part - rituximab-naïve.

Superior outcome of women with stage I/II cutaneous melanoma: pooled analysis of four European Organisation for Research and Treatment of Cancer phase III trials.

PURPOSE: Several studies observed a female advantage in the prognosis of cutaneous melanoma, for which behavioral factors or an underlying biologic mechanism might be responsible. Using complete and reliable follow-up data from four phase III trials of the European Organisation for Research and Treatment of Cancer (EORTC) Melanoma Group, we explored the female advantage across multiple end points and in relation to other important prognostic indicators. PATIENTS AND METHODS: Patients diagnosed with localized melanoma were included in EORTC adjuvant treatment trials 18832, 18871, 18952, and 18961 and randomly assigned during the period of 1984 to 2005. Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% CIs for women compared with men, adjusted for age, Breslow thickness, body site, ulceration, performed lymph node dissection, and treatment. RESULTS: A total of 2,672 patients with stage I/II melanoma were included. Women had a highly consistent and independent advantage in overall survival (adjusted HR, 0.70; 95% CI, 0.59 to 0.83), disease-specific survival (adjusted HR, 0.74; 95% CI, 0.62 to 0.88), time to lymph node metastasis (adjusted HR, 0.70; 95% CI, 0.51 to 0.96), and time to distant metastasis (adjusted HR, 0.69; 95% CI, 0.59 to 0.81). Subgroup analysis showed that the female advantage was consistent across all prognostic subgroups (with the possible exception of head and neck melanomas) and in pre- and postmenopausal age groups. CONCLUSION: Women have a consistent and independent relative advantage in all aspects of the progression of localized melanoma of approximately 30%, most likely caused by an underlying biologic sex difference.