991 resultados para 1755 Lisbon Tsunami


Relevância:

40.00% 40.00%

Publicador:

Resumo:

Tsunamis are highly energetic events that may destructively impact the coast. Resolving the degree of coastal resilience to tsunamis is extremely difficult and sometimes impossible. In part, our understanding is constrained by the limited number of contemporaneous examples and by the high dynamism of coastal systems. In fact, longterm changes of coastal systems can mask the evidence of past tsunamis, leaving us a short or incomplete sedimentary archive. Here, we present a multidisciplinary approach involving sedimentological, geomorphological and geophysical analyses and numerical modelling of the AD 1755 tsunami flood on a coastal segment located within the southern coast of Portugal. In particular, the work focuses on deciphering the impact of the tsunami waves over a coastal sand barrier enclosing two lowlands largely inundated by the tsunami flood. Erosional features documented by geophysical data were assigned to the AD 1755 eventwith support of sedimentological and age estimation results. Furthermore, these features allowed the calibration of the simulation settings to reconstruct the local conditions and establish the run-up range of the AD 1755 tsunami when it hit this coast (6– 8 m above mean sea level). Our work highlights the usefulness of erosional imprints preserved in the sediment record to interpret the impact of the extreme events on sand barriers

Relevância:

40.00% 40.00%

Publicador:

Resumo:

City & Spectacle: a vision of pre-earthquake Lisbon consists of a virtual recrea on of the city of Lis- bon on the eve of the great earthquake of 1 November 1755, giving shape to a laboratory model for research into the city’s history. As its star ng point the project has the virtual recrea on of one the most emblema c of spaces from 18th century Lisbon, the Royal Opera House, which disappeared during the 1755 earthquake. The recrea on of the Opera House was developed in the scope of the commemora- ons of the 250th anniversary of the 1755 catastrophe as an a empt to restore this space of the highest ar s c quality to memory and to return it to the inventory of the Portuguese heritage of architectural history.1 Using Second Life® technology it was possible to put forward a model of both the struc- ture and interiors of the Opera House as well as its anima on combined with a small piece of the opera presented at the inaugura on of the building in April 1755. The public presenta on of this virtual model at the conference 1755: Catástrofe, memória e arte (1755: catastrophe, memory and art), which took place at the Centro de Estudos Compara- stas, Universidade de Lisboa, led to a debate on the study and cri cal analysis of documentary sources and their selec on and applica on on recrea ons using virtual world technology. It also emphasized the need to extend the research on pre-earthquake Lisbon.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The Gulf of Cadiz, as part of the Azores-Gibraltar plate boundary, is recognized as a potential source of big earthquakes and tsunamis that may affect the bordering countries, as occurred on 1 November 1755. Preparing for the future, Portugal is establishing a national tsunami warning system in which the threat caused by any large-magnitude earthquake in the area is estimated from a comprehensive database of scenarios. In this paper we summarize the knowledge about the active tectonics in the Gulf of Cadiz and integrate the available seismological information in order to propose the generation model of destructive tsunamis to be applied in tsunami warnings. The fault model derived is then used to estimate the recurrence of large earthquakes using the fault slip rates obtained by Cunha et al. (2012) from thin-sheet neotectonic modelling. Finally we evaluate the consistency of seismicity rates derived from historical and instrumental catalogues with the convergence rates between Eurasia and Nubia given by plate kinematic models.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The Chiado’s fire that affected the city centre of Lisbon (Portugal) occurred on 25th August 1988 and had a significant human and environmental impact. This fire was considered the most significant hazard to have occurred in Lisbon city centre after the major earthquake of 1755. A clear signature of this fire is found in the atmospheric electric field data recorded at Portela meteorological station about 8 km NE from the site where the fire started at Chiado. Measurements were made using a Benndorf electrograph with a probe at 1 m height. The atmospheric electric field reached 510 V/m when the wind direction was coming from SW to NE, favourable to the transport of the smoke plume from Chiado to Portela. Such observations agree with predictions using Hysplit air mass trajectory modelling and have been used to estimate the smoke concentration to be ~0.4 mg/m3. It is demonstrated that atmospheric electric field measurements were therefore extremely sensitive to Chiado’s fire. This result is of particular current interest in using networks of atmospheric electric field sensors to complement existing optical and meteorological observations for fire monitoring.

Relevância:

30.00% 30.00%

Publicador:

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Sea Surface Temperature (SST), river discharge and biological productivity have been reconstructed from a multi-proxy study of a high-temporal-resolution sedimentary sequence recovered from the Tagus deposition center off Lisbon (Portugal) for the last 2000 years. SST shows 2 °C variability on a century scale that allows the identification of the Medieval Warm Period (MWP) and the Little Ice Age (LIA). High Iron (Fe) and fine-sediment deposition accompanied by high n-alkane concentrations and presence of freshwater diatoms during the LIA (1300-1900 AD) (Science 292 (2001) 662) suggest augmented river discharge, whereas higher total-alkenone concentrations point to increased river-induced productivity. During the MWP (550-1300 AD) (Science 292 (2001) 662) larger mean-grain size and low values of magnetic susceptibility, and concentrations of Fe, n-alkanes, and n-alcohols are interpreted to reflect decreased runoff. At the same time, increased benthic and planktonic foraminifera abundances and presence of upwelling related diatoms point to increased oceanic productivity. On the basis of the excellent match found between the negative phases of the North Atlantic Oscillation (NAO) index and the intensified Tagus River discharge observed for the last century, it is hypothesized that the increased influx of terrigenous material during the LIA reflects a negative NAO-like state or the occurrence of frequent extreme NAO minima. During the milder few centuries of the MWP, stronger coastal upwelling conditions are attributed to a persistent, positive NAO-like state or the frequent occurrence of extreme NAO maxima. The peak in magnetic susceptibility, centered at 90 cm composite core depth (ccd), is interpreted as the result of the well-known 1755 AD Lisbon earthquake. The Lisbon earthquake and accompanying tsunami are estimated to have caused the loss of 39 cm of sediment (355 years of record-most of the LIA) and the instantaneous deposition of a 19-cm sediment bed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

James Parkinson (1755-1824) of Parkinson's disease, is well recognized as a pioneer of clinical neurology; and is even more famous as a founder of modem palaeontology. We have reviewed from primary sources his extensive contributions to clinical child care and his pioneering advocacy for child welfare, protection and safety. His writings, outreach and advocacy for children's health characterizes him as one whose influence was an important springboard from which evolved the modern specialty of paediatrics. Parkinson was one of the first to write on child-rearing practices and in this context antedated Benjamin Spock by 150 years. Parkinson was a pioneer of child safety and the prevention of childhood trauma. He wrote of the resuscitation of near-drowned children and of first aid for injured children. This critical analysis reviews his pioneering description of child abuse and the development of post-abuse hydrocephalus. He wrote the datum description (in English) of the pathophysiology and pathology of appendicitis in children, of fatal rabies in children and highlighted the risk of death even when the biting dog was not clinically rabid. His advocacy for social reform for children's welfare was courageous and pioneering. James Parkinson, hitherto unacknowledged, was a significant founder of the evolving discipline of paediatrics and child health.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Dividends and their distribution decisions, being a component of the compensation of investors are a constant financial worry within companies, thus revealing one of the themes highlighted in the context of the financial literature. Study will address the factors determining the dividend policy practiced by companies listed in the Portuguese stock market. The latter will be 47 non-financial companies listed on the Euronext Lisbon during 2009 until 2011. The two samples that have been investigated include the representative of the majority of non-financial companies listed on Euronext Lisbon and the other financial companies members of the PSI 20. The methodology adopted is one of the ordinary least squares regression and the amount of dividends per share distributed was used in determining the dependent variable. In relation to the independent variables, six explanatory factors were chosen. These include profitability, stability of dividend policy, size, growth, risk and investment opportunities. The conclusion suggests that the most important factors to explain the amount of dividends distributed are profitability and stability of dividend policy. There after, growth and risk factors, as well as factors that explain the amount of dividends distributed are also relevant. The remaining variables obtained were insufficient evidence pointing to a significant effect in explaining the dividend policy of Portuguese companies in the sample. The conclusion also states that differences exist in the importance of the explanatory factors to the amount of dividends distributed between the study samples, given the differentiation of dividend policies, followed by companies from each group analyzed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The problematic of dividends paid out by firms has deserved the attention of several studies, theoretical and empirical, on corporate finance. This article intends to contribute to the theme by determining the factors that influence a firm’s dividends` policy. In this sense, it investigates the effect of a set of factors on the dividends paid out by issuing non financial firms belonging to Euronext Lisbon. Results suggest the existence of firm specific characteristics influencing its dividends policy. A firm’s Cash-flow and its stocks` market price seem to have a positive impact on the dividends paid out to stockholders. In issuing non financial firms that belong to the PSI 20 Index results additionally show the existence of a negative effect of net profits on dividend’s payment.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Sendo os dividendos uma componente da remuneração dos investidores e as decisões de distribuição, uma constante preocupação financeira no seio das empresas, revela-se a importância do tema em continuo destaque no contexto da literatura financeira. Na presente dissertação estudam-se quais os factores determinantes da politica de dividendos praticados pelas empresas cotadas no mercado de capitais português. Em particular procurou.-se averiguar qual o efeito que um conjunto de factores económicos-financeiros específicos á empresa exerce sobre o montante de distribuição de dividendos das empresas não financeiras emitentes que integram a Euronext Lisbon. Incidindo sobre 47 empresas não financeiras cotadas na Euronext Lisbon durante o período temporal de 2009 a 2011, definiu-se duas amostras, uma representativa de generalidade das empresas não financeiras cotadas na Euronext Lisbon e outra apenas sobre as empresas não financeiras integrantes do PSI 290. De acordo com as premissas do estudo adotou-se a metodologia de regressão dos mínimos quadrados ordinários e escolheu-se as variáveis de inclusão no modelo. Em relação á variável dependente utilizou-se o montante de dividendos por acção distribuídos. Em relação ás variáveis independentes escolheram-se seis factores explicativos:rendibilidade, estabilidade da politica de dividendos, dimensão, crescimento, risco e oportunidades de investimento. As conclusões obtidas sugerem que os factores ais importantes á explicação do montante de dividendos distribuídos são a rendibilidade e a estabilidade da politica de dividendos. Logo a seguir aparecem os factores crescimento e risco, como factores também explicativos do montante de dividendos distribuídos. Quanto ás restantes variáveis não se obteve evidencias suficientes que apontem para um efeito significativo na exposição da politica de dividendos das empresas portuguesas incluídas na amostra. Conclui-se ainda existirem divergências na importância dos factores explicativos no montante de dividendos distribuídos entre as amostras do estudo, da da a diferenciação das politicas de dividendos, seguidas pelas empresas de cada grupo analisado.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

O objectivo principal da presente dissertação, é determinar o grau de cumprimento e controlo do relato financeiro, em termos de divulgação de matérias ambientais, das empresas cotadas Euronext Lisbon e na Nyse Euronext. Em termos de metodologia, efectuámos uma análise de conteúdo à informação contabilística, publicada pelas empresas-alvo no ano de 2007, utilizando as técnicas univariada, bivariada e multivariada. Por fim, construímos um índice baseado na análise das componentes principais. Depois de analisar quais os factores que mais influenciam o relato financeiro em termos de divulgação de matérias ambientais, chegámos à conclusão que o “Capital Próprio” está negativamente correlacionado com a certificação externa, quer para as empresas cotadas na Euronext Lisbon, quer para as empresas cotadas na Nyse Euronext. Já o factor “Resultado Líquido” está negativamente correlacionado, para as empresas cotadas na Euronext Lisbon, com as divulgações ambientais presentes no relatório de gestão, e positivamente correlacionado, para as empresas cotadas na Nyse Euronext, com a existência de um relatório de sustentabilidade. No que diz respeito ao factor “Volume de Negócios”, este encontra-se directamente relacionado, para as empresas cotadas na Euronext Lisbon, com as divulgações contabilísticas de matérias ambientais. Por seu lado, para as empresas cotadas na Nyse Euronext, as divulgações contabilísticas de matérias ambientais estão directamente relacionadas com o factor “Sector de Actividade”. Em termos de análise multivariada, agrupámos um conjunto de factores, relacionados com o cumprimento e controlo do relato financeiro de matérias ambientais, em quatro dimensões (“Melhoria da Divulgação e Certificação”, “Melhoria da Medição”, Melhoria da Qualidade”, e “Melhoria do Controlo”), com o intuito de compreender qual é considerada como mais importante aquando da construção deste tipo de informações, para cada um dos grupos estudados. Aqui, chegámos à conclusão que, para ambos os grupos, a atenção é mais focada para a “Melhoria da Divulgação e Certificação”. Relativamente ao índice global, construído a partir da análise multivariada efectuada, é unânime para ambos os grupos de empresas que a dimensão “Melhoria do Controlo” é a que se revela menos significante na divulgação de matérias ambientais. Na construção deste índice global, é notório que as empresas cotadas na Nyse Euronext, ainda que não possuam um normativo sobre o relato financeiro de matérias ambientais, obtém uma classificação mais elevada (0,33 versus 0,25), no que diz respeito ao seu controlo e cumprimento do relato financeiro de matérias ambientais, quando comparadas com as empresas cotadas Euronext Lisbon. Com os resultados obtidos, concluímos que as empresas cotadas na Euronext Lisbon têm um menor grau de controlo e cumprimento relativamente às empresas cotadas na Nyse Euronext, no que diz respeito à divulgação de matérias ambientais.