Adomian decomposition method, nonlinear equations and spectral solutions of burgers equation

Tese de doutoramento. Ciências da Engenharia. 2006. Faculdade de Engenharia. Universidade do Porto, Instituto Superior Técnico. Universidade Técnica de Lisbo

Financial Risk Analysis of Portuguese Textile and Tourism Companies

Textile and tourism sectors are two important industries in the Portuguese economy. However, its high exposure to both internal and international economic volatility make the companies operating in these economic sectors particularly vulnerable to economic crises, such as the ones which have been impacting Portugal and the European Union. The objective of this paper is to evaluate and understand the impact of size and age on the financial health of textile and tourism companies, measured by economic indices. An empirical based model is proposed. Its implications are derived and tested on a sample of 4061 Portuguese companies from textile and tourism sectors, during the period 2005-2009. The findings suggest that age has a major impact on the risk of failure, rather than size. Whereas the effect of age is generally positive regarding the financial health of the company, the effect of size is less clear and ultimately depends on the age of the company. DOI: 10.5901/mjss.2015.v6n3p47

Causas de hipocromia e microcitose em dadores de sangue do Centro Regional de Sangue de Coimbra

Mestrado em Métodos BiomolecularesA hemoglobina é um polipeptido em forma de tetrâmero, constituído por um grupo heme e por dois pares de cadeias globínicas α (ζ, α1, α2) e não-α (β, δ, Aγ, Gγ, ε) que se associam em diversas combinações formando diferentes hemoglobinas. Nos adultos, a príncipal hemoglobina sintetizada é a HbA (α2β2), contribuindo para cerca de 95% do total da hemoglobina. A restante hemoglobina é constituída por pequenas quantidades de Hb A2 (α2δ2) (<3,5%) e de Hb F (<2 %). As talassémias caracterizam-se por uma produção insuficiente de uma das cadeias globínicas. No adulto a diminuição de síntese de cadeias α ou β leva a uma diminuição de produção de HbA resultando numa eritropoiese ineficaz. Nos portadores de talassémia, a hemoglobina (Hb), o volume globular médio (VGM) e a hemoglobina globular médio (HGM) estão abaixo dos valores de referência, tendo em conta a idade e sexo. São designadas por anemias microcíticas e hipocrómicas. O principal objectivo deste trabalho foi estudar as causas de hipocromia e microcitose num grupo de 50 dadores de sangue do Centro Regional de Sangue de Coimbra. A principal causa detectada foi a alfa-talassemia, sendo a mutação mais frequente a -α3.7 encontrada em heterozigotia em 10 indivíduos, seguida da variante talassémica Hb Plasencia (4 portadores), da delecção –α4.2 também em heterozigotia (2 casos) e 1 heterozigotia composta –α3.7/–α4.2. Foram ainda detectadas 4 mutações intrónicas no gene globínico α2, não descritas na literatura. Dos restantes, 8 individuos eram portadores de β-talassémias e 2 portadores de Hb Lepore. O conhecimento das causas mais frequentes de hipocromia e microcitose e das respectivas bases moleculares apresenta grandes vantagens em saúde pública, nomeadamente, para a detecção e informação dos portadores e caracterização molecular dos casais de risco. Um acompanhamento adequado em consultas da especialidade e, quando necessário, o diagnóstico pré-natal ajudam a diminuir o número de recémnascidos afectados com as formas graves das patologias associadas (Talassemia Major/ Intermédia e Drepanocitose). ABSTRACT: Hemoglobin is a tetramer of polypeptides consisting of a heme group and two pairs of α globin chains (ζ, α1, α2) and non-α globin chains (β, δ, ε, Aγ, Gγ) that form different hemoglobins types. The main hemoglobin in adults is the HbA (α2β2), representing about 95% of the total hemoglobin. The remaining hemoglobins consists of small quantities of Hb A2 (α2δ2) (<3.5%) and Hb F (<2%). The thalassemias are due to an insufficient production of globin chains resulting in decrease Hb synthesis and ineffective erythropoiesis. The haemoglobin, mean corpuscular volume (VGM) and mean cell haemoglobin (HGM) are below the reference values for age and sex. This phenotype is called microcytic, hypochromic anaemias. The main aim of this study is to identify the ethiology of microcytosis and hypochromia in 50 blood donors of the Centro Regional de Sangue de Coimbra. The principal cause detected was alpha-thalasemia and the most frequent mutation was –α3.7 found in heterozygous state in 10 samples, followed by 8 carriers of β- thalassemia, 4 Hb Plasencia carriers, 2 Hb Lepore carriers, 2 –α4.2 heterozygous and 1 compound heterozygous –α3.7/–α4.2. We also found 4 not previous descibed intronic mutations in the α2 globin gene. The knowledge of the most frequent causes of hypocromia and microcytosis, and their molecular bases, has many advantages in public health to define the strategy for carriers detection, the genetic conselling of couples at risk of conceiving fetuses with severe forms of anaemia (Thalassemia Major/Intermedia and Sickle Cell disease), and for prenatal diagnosis

Prediction business failure with logit and discriminant analysis: evidence from portuguese hospitality sector

O turismo é um setor em forte expansão em Portugal e com um importante contributo na economia portuguesa. Por isso, o equilíbrio financeiro das empresas neste setor reveste-se da maior relevância, quer para os agentes económicos, quer para os decisores políticos. Apesar disso, não existem em Portugal trabalhos de investigação que analisem o fracasso empresarial no setor da hotelaria. O objetivo principal deste estudo é propor um modelo de antecipação do fracasso empresarial, especificamente desenvolvido para o setor hoteleiro português. Para esse efeito, utilizamos uma amostra de empresas do sector à qual aplicamos a análise discriminante e a técnica logit. Os resultados obtidos mostram um elevado grau de ajustamento do modelo aos dados e indicam que o modelo utilizado constitui um importante contributo na definição de políticas macroeconómicas e programas de apoio ao desenvolvimento do turismo, sendo igualmente relevantes para as decisões de investidores e credores.ABSTRACT: In hospitality and tourism sector, the financial stability of companies has been an issue of major concern, both for economic actors and policymakers. Literature offers us a wide and rich diversity of studies on the issue. Regarding to Portugal, there are studies applied to different economic sectors. However, only a little few have investigated about the hospitality industry. The main goal of this paper is to develop econometric and multivariate models for forecasting business failure in the hospitality industry, using the logit and discriminant analysis. The results show a high degree of adjustment of the model.The practical utility of these models is recognized by different users of accounting documents, particularly investors and creditors. These models also make an important contribution for the definition of macroeconomic policies and public funding programs for investment in tourism sector.info:eu-repo/semantics/publishedVersio

Large ferro–pyro–phototronic effect in 0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3 thin films integrated on silicon for photodetection

Coupling together the ferroelectric, pyroelectric, and photovoltaic characteristics within a single material is a novel way to improve the performance of photodetectors. In this work, we take advantage of the triple multifunctionality shown by 0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3 (BCZT), as demonstrated in an Al/Si/SiOx/BCZT/ITO thin-film device. The Si/SiOx acts as an n-type layer to form a metal–ferroelectric–insulator–semiconductor heterostructure with the BCZT, and with Al and ITO as electrodes. The photo-response of the device, with excitation from a violet laser (405 nm wavelength), is carefully investigated, and it is shown that the photodetector performance is invariant with the chopper frequency owing to the pyro-phototronic effect, which corresponds to the coupling together of the pyroelectric and photovoltaic responses. However, the photodetector performance was significantly better than that of the devices operating based only on the pyro-phototronic effect by a factor of 4, due to the presence of ferroelectricity in the system. Thus, after a poling voltage of −15 V, for a laser power density of 230 mW/cm2 and at a chopper frequency of 400 Hz, optimized responsivity, detectivity, and sensitivity values of 13.1 mA/W, 1.7 × 1010 Jones, and 26.9, respectively, are achieved. Furthermore, ultrafast rise and fall times of 2.4 and 1.5 µs, respectively, are obtained, which are 35,000 and 36,000 times faster rise and fall responses, respectively, than previous reports of devices with the ferro–pyro–phototronic effect. This is understood based on the much faster ferroelectric switching in ferroelectric thin films owing to the predominant 180° domains in a single direction out of plane.This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding Contracts UIDB/04650/2020. This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 958174 (M-ERA-NET3/0003/2021—NanOx4EStor). The authors would also like to thank engineer José Santos for technical support at the Thin Film Laboratory. J. L. M.-D. and R. L. Z. H. are grateful for EPSRC CAM-IES grant EP/P007767/. R. L. Z. H. also acknowledges support from the Royal Academy of Engineering under the Research Fellowships scheme (No.: RF\201718\1701). J. L. M.-D. acknowledges support from the Royal Academy of Engineering Chair in Emerging Technologies scheme (No.: CIET1819_24) and the ERC grant EROS, EU-H2020-ERC-ADG # 882929

EAIR 41st Annual Forum in Leiden, The Netherlands 25 till 28 August 2019

Trabalho apresentado em EAIR 41st Annual Forum, 25-28 agosto 2019, Leiden, Países Baixos.Polytechnic Institutes in Portugal: research on the impact of twelve institutes on the local economy Higher Education Institutions are recognized as important actors in regional development. The Portuguese higher education system comprises both Universities and Polytechnic Institutes, which face an increasing pressure to demonstrate that their presence has an impact on the surrounding communities contributing to their economic development. This paper presents the estimation of the economic impact of twelve Polytechnic Institutes, located in quite diverse regions, based on a shared model so that comparisons have a collective framework of analysis. The main results obtained show that the economic impact ranged from 1.8% to 10.6% of the local GDP and that these Institutes are major local employers.info:eu-repo/semantics/publishedVersio

Clareza, concisão e coesão: princípios e métricas de legibilidade aplicados ao texto de pós-graduandos em Ciência da Informação

Introdução: a barreira da língua dificulta publicar em inglês mesmo quando há mérito científico, pois o problema começa em português, na dificuldade em escrever como a ciência requer. Qual o impacto da aplicação de princípios de clareza, concisão e coesão na extensão e legibilidade de textos científicos? Esta pesquisa objetivou verificar esse impacto ao comparar extensão e indicadores de legibilidade antes e após a aplicação dos princípios. Método: vinte e cinco estudantes de pós-graduação em Ciência da Informação anotaram um texto científico próprio e o de três colegas, em revisão por pares duplo-cega, indicando problemas de estilo de quatro tipos: palavra desnecessária, distância sujeito-verbo excessiva, nominalização excessiva e contextualização tardia. Cada autor reelaborou seu próprio texto para resolver os problemas anotados. Os textos originais e reelaborados foram comparados em extensão e escore de facilidade de leitura de Flesch. Textos originais e reelaborados da literatura também foram mensurados como referência. Resultados: Todos os textos diminuíram em extensão após reelaborados, embora tenha havido mais atenção a problemas gramaticais do que aos quatro problemas de estilo. Houve 13 aumentos, duas manutenções e 10 diminuições nos escores de legibilidade. Esse resultado é compatível com o estudo-referência com textos da literatura. Conclusão: a aplicação dos princípios de legibilidade diminui a extensão e, em acordo com a literatura, tem impacto duvidoso no escore de legibilidade. Resta investigar a traduzibilidade comparada para verificar o pressuposto de que aplicar os princípios é "escrever em inglês em português".Introduction: The language barrier makes it difficult to publish in English, even when there is scientific merit, as the problem starts in Portuguese, in the difficulty of following scientific writing principles. What is the impact of applying principles of clarity, conciseness, and cohesion in the extension and readability of scientific texts? This research aimed to verify this impact when comparing extension and readability indicators before and after applying those principles. Method: Twenty-five Information Science graduate students annotated their own scientific text and that of three colleagues, in a double-blind review, indicating writing style problems of four types: unnecessary word, excessive subject-verb distance, excessive nominalization, and late contextualization. Each author then reworked their own text to solve the problems. The original and reworked texts were compared in length and Flesch Reading Ease score. Original and reworked texts from the literature were also compared, as a reference. Results: All texts were shortened after rework, although annotations were directed most to grammatical problems than to the four style problems. There were 13 increases, 2 maintenance, and 10 decreases in the readability scores. This result is compatible with the benchmark study with texts from the literature. Conclusions: Applying readability principles improves conciseness but, in accordance with the literature, has a dubious impact on the readability score. Compared translatability remains an open research topic, to verify the assumption that applying the principles equates to "write in English in Portuguese"

MAMMALS IN PORTUGAL : A data set of terrestrial, volant, and marine mammal occurrences in P ortugal

Mammals are threatened worldwide, with 26% of all species being includedin the IUCN threatened categories. This overall pattern is primarily associatedwith habitat loss or degradation, and human persecution for terrestrial mam-mals, and pollution, open net fishing, climate change, and prey depletion formarine mammals. Mammals play a key role in maintaining ecosystems func-tionality and resilience, and therefore information on their distribution is cru-cial to delineate and support conservation actions. MAMMALS INPORTUGAL is a publicly available data set compiling unpublishedgeoreferenced occurrence records of 92 terrestrial, volant, and marine mam-mals in mainland Portugal and archipelagos of the Azores and Madeira thatincludes 105,026 data entries between 1873 and 2021 (72% of the data occur-ring in 2000 and 2021). The methods used to collect the data were: live obser-vations/captures (43%), sign surveys (35%), camera trapping (16%),bioacoustics surveys (4%) and radiotracking, and inquiries that represent lessthan 1% of the records. The data set includes 13 types of records: (1) burrowsjsoil moundsjtunnel, (2) capture, (3) colony, (4) dead animaljhairjskullsjjaws, (5) genetic confirmation, (6) inquiries, (7) observation of live animal (8),observation in shelters, (9) photo trappingjvideo, (10) predators dietjpelletsjpine cones/nuts, (11) scatjtrackjditch, (12) telemetry and (13) vocalizationjecholocation. The spatial uncertainty of most records ranges between 0 and100 m (76%). Rodentia (n=31,573) has the highest number of records followedby Chiroptera (n=18,857), Carnivora (n=18,594), Lagomorpha (n=17,496),Cetartiodactyla (n=11,568) and Eulipotyphla (n=7008). The data setincludes records of species classified by the IUCN as threatened(e.g.,Oryctolagus cuniculus[n=12,159],Monachus monachus[n=1,512],andLynx pardinus[n=197]). We believe that this data set may stimulate thepublication of other European countries data sets that would certainly contrib-ute to ecology and conservation-related research, and therefore assisting onthe development of more accurate and tailored conservation managementstrategies for each species. There are no copyright restrictions; please cite thisdata paper when the data are used in publications.info:eu-repo/semantics/publishedVersio