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  • Approaches for Optimizing Virtual Machine Placement and Migration in Cloud Environments
    Publication . Filho, Manoel C. Silva; Monteiro, Cláudio C.; Inácio, Pedro R. M.; Freire, Mário
    Cloud computing is a model for providing computing resources as a utility which faces several challenges on management of virtualized resources. Accordingly, virtual machine placement and migration are crucial to achieve multiple and conflicting goals. Regarding the complexity of these tasks and plethora of existing proposals, this work surveys the state-of-the-art in the area. It presents a cloud computing background, a review of several proposals, a discussion of problem formulations, advantages and shortcomings of reviewed works. Furthermore, it highlights the challenges for new solutions and provides several open issues, showing the relevancy of the topic in an increasing and demanding market.
    2018-01Journal article Restricted access Show more
  • A bat optimized neural network and wavelet transform approach for short-term price forecasting
    Publication . Bento, P.M.R.; Pombo, José Álvaro Nunes; Calado, M. do Rosário; Mariano, S.
    In the competitive power industry environment, electricity price forecasting is a fundamental task when market participants decide upon bidding strategies. This has led researchers in the last years to intensely search for accurate forecasting methods, contributing to better risk assessment, with significant financial repercussions. This paper presents a hybrid method that combines similar and recent day-based selection, correlation and wavelet analysis in a pre-processing stage. Afterwards a feedforward neural network is used alongside Bat and Scaled Conjugate Gradient Algorithms to improve the traditional neural network learning capability. Another feature is the method's capacity to fine-tune neural network architecture and wavelet decomposition, for which there is no optimal paradigm. Numerical testing was applied in a day-ahead framework to historical data pertaining to Spanish and Pennsylvania-New Jersey-Maryland (PJM) electricity markets, revealing positive forecasting results in comparison with other state-of-the-art methods.
    2018-01Journal article Restricted access Show more
  • Ventilação Não Invasiva: Experiência de um Serviço de Medicina Interna
    Publication . Costa, José Coutinho; Machado, João Neiva; Costa, Joana; Fortuna, Jorge; Gama, Jorge; Rodrigues, Cidália
    Introdução: A ventilação não invasiva (VNI) é uma forma de suporte ventilatório não invasivo, com benefícios comprovados em diversas patologias. O objetivo foi avaliar as indicações da VNI em doentes com insuficiência respiratória e identificar fatores preditivos da resposta à VNI. Material e Métodos: Análise retrospetiva dos processos clínicos de doentes submetidos a VNI, internados no Serviço de Medicina, entre Janeiro e Dezembro de 2014. Resultados: Incluídos 54 doentes, com idade média de 82,2 anos (± 8,4). Quarenta e quatro doentes apresentavam patologias que são consideradas indicações, com níveis de evidência estabelecida, para utilização de VNI: 33 (75,0%) tinham insuficiência cardíaca descompensada, cinco (11,4%) exacerbação aguda da doença pulmonar obstrutiva crónica, quatro (9,1%) síndrome de obesidade-hipoventilação e dois (4,5%) pneumonia no imunocomprometido. A taxa de falência foi 20,5%. Nos restantes doentes, a VNI foi utilizada na pneumonia no imunocompetente, choque séptico e intoxicação por benzodiazepinas. A taxa de falência foi 70,0%. Verificou-se uma melhoria estatisticamente significativa nos parâmetros gasométricos duas horas após a VNI nos doentes com patologia com níveis de evidência estabelecida para VNI e nos doentes em que não houve falência desta modalidade ventilatória. Conclusão: Na nossa amostra a taxa falência da VNI foi bastante inferior nos doentes que cumpriam as indicações formais para a VNI. Assim, apesar da crescente utilização da VNI, a seleção criteriosa dos doentes constitui uma etapa essencial para o seu sucesso. O melhor preditor do sucesso da VNI foi a boa resposta após 1 a 2 horas de terapêutica.
    2018-01Journal article Open access Show more
  • Applications of low energy mev ion beams and computer simulation to surface analysis of materials
    Publication . Carvalho, José Pacheco de; Pacheco, Cláudia Ribeiro; Reis, António
    This work is about surface analysis by nuclear techniques, which are essentially non-destructive, and computer simulation. The energy analysis method for nuclear reaction analysis is used. Elastic scattering is a particular and important case. Energy spectra are computer simulated and compared to experimental data, giving target composition and concentration profile information. The simulations use, mainly, target parameterization and available nuclear data. The method is successfully applied to determination of a uniform concentration profile of 18O from the (p,α) reaction in a thick oxide target. Uniform concentration profiles of 12C are obtained from the (d,p) reaction for a thick target. Uniform concentration profiles of 16O are also obtained from (d,p) and (d,α) reactions along large depths. Elastic scattering is used for depth profiling of Al and O in a thick target.
    2018-01Conference object Open access Show more
  • Effects of knowing the task duration on players' pacing patterns during soccer small-sided games
    Publication . Ferraz, Ricardo; Gonçalves, Bruno; Tillaar, Roland Van Den; Rodríguez Jiménez, Sergio; Sampaio, Jaime; Marques, Mário C.
    The aim of this study was to identify the influence of prior knowledge of exercise duration on players' pacing patterns during soccer small-sided games. Twenty semi-professional male soccer players participated in this study. In the first game scenario, players were not informed how long they would be required to play the small-sided game and the activity was terminated after 20 min (Unknown Condition). In the second game scenario, players were told that they would play the small-sided game for 10 min, but immediately after completing the 10-min game, they were asked to complete another 10 min (Partially Condition). In the third game scenario, players were instructed that they would play the small-sided game for 20 min and then they completed the 20-min game (Known Condition). The results presented a tendency of higher values in all performance variables in the [0'-10'] min compared with the [10'-20'] min. As the players' previous knowledge about the tasks duration increased, the performance between two moments tended to be similar. Considering the entire 20-min game duration, the Partially Condition of the exercise was the most demanding condition. In conclusion, the knowledge of shorter durations of the exercise seems to lead to an increase of exercise duration demand, and longer exercise durations possibly tend to decrease differences between full knowledge and not knowing the exercise duration.
    2018-01Journal article Open access Show more
  • Comportamento alimentar infantil e atitudes parentais face à alimentação das crianças
    Publication . Silva, Cláudia Mendes Da; Teixeira, Tânia
    A infância é um período crítico para o desenvolvimento de comporta - mentos relativos à alimentação e é considerada fulcral na prevenção do excesso de peso, da doença e na promoção da saúde [...]
    2018-01Conference object Open access Show more
  • Preclinical performance of vaginal semisolid products: technological and safety evaluations assuming physiologic parameters
    Publication . Machado, Rita Solange Monteiro; Oliveira, José António Martinez Souto de; Oliveira, Rita Manuela Palmeira de
    Vaginal semisolid products preclinical evaluations, when performed considering the particularities of the target organ, may represent key tools to predict in vivo performance. Before heading to clinical phases, vaginal semisolids must demonstrate to have an adequate technological and safety profile, in order to achieve higher success rates in the human testing stage. Traditional characterization methods currently used for vaginal semisolids do not undertake an integrative approach, since they do not address, for example, vaginal pH, fluid and temperature. Moreover, early safety assessment methods are largely described and validated not only on scientific literature, but also by regulatory agencies, although they are still mainly focused on cellular-based models. This safety profile of products can be further improved by combining toxicity testing, with drug release and permeation studies. Indeed, the vaginal administration route allows for local and systemic delivery of drugs, depending on the therapeutic purpose. Consequently, the drug should be confined to the chosen location of administration, to obtain maximum efficacy while avoiding side effects. The aim of this work was to develop a full set of assessment methods for characterization of vaginal semisolid products. Commercialized formulations were used to establish new methodological approaches that could be applied in new products development and characterization. Therefore, antimicrobials, Gino-canesten®, Sertopic®, Dermofix®, Gyno-pevaryl®, Lomexin®, Gino Travogen®, Dalacin V®; oestrogens, Ovestin®, Blissel® and Colpotrophine®; and, two reference formulations, Universal Placebo and Replens® were extensively evaluated. Technologically, they were tested in terms of pH, pH-buffering capacity, osmolality, textural parameters and viscosity, using a physiologic standpoint that considered the body temperature and dilution in a physiologic volume of vaginal fluid simulant (VFS); and even an ex vivo porcine model to infer bioadhesion and rheology on an after-administration environment. In terms of safety investigation, cellular toxicity was disclosed on VK2 E6/E7, HeLa and HEC-1A cell-lines, using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and NRU (Neutral Red Uptake) assays. Tissue explants, collected from the ex vivo porcine vaginal model, were also tested concerning toxicity, through MTT and histological analysis. Moreover, to include an advanced in vitro toxicity evaluation, the HET-CAM (Hen's Egg Test – Chorioallantoic Membrane), already in validation for eye irritation testing, was applied to vaginal irritation. A HPLC-DAD (High Performance Liquid Chromatography with Diode Array Detector) quantification method for the molecules present in semisolids included in this work, was developed and validated according to FDA (Food and Drug Administration - USA), EMA (European Medicines Agency) and ICH (International Conference for Harmonization) requirements. Further, this method was applied in drug quantification on in vitro drug release and ex vivo drug permeation experiments. These two techniques were performed using dynamic vertical Franz diffusion cells, having all experimental setting being specifically designed and optimized concerning the molecules in study (estriol, clotrimazole, econazole, isoconazole, sertaconazole and fenticonazole). Concerning technological characteristics, antimicrobial formulations exhibited lower pH than topical oestrogens. Buffering capacity in a vaginal fluid simulant conducted to better predictions of what happens in vivo. Characterization was performed also for those less acidic products to assess their ability to gain physiologic pH after mixing with simulated vaginal fluids. Products osmolality after dilution in VFS were below the upper limit advised by the World Health Organization (WHO). The antimicrobials had similar textural behaviours, while topical oestrogens varied in textural parameters. A slight decrease in viscosity was observed after application of dilution and temperature factors, showing the influence of the surrogate vaginal environment, while maintaining their pseudoplastic behaviour. However, each formulation had its own profile, possibly driven by their composition. Formulations’ viscosity was higher when tested using the ex vivo administration model than when only diluted in VFS at 37ºC. Concerning the in vitro models, VK2 E6/E7, presented relatively higher viabilities than HeLa and HEC-1A cells over the tested product concentrations. Tissue viability results were much higher than those obtained for the in vitro cellular models, revealing that this model could be more robust and closer to the in vivo situation. Across models, antimicrobials showed concentration-dependent viabilities. While oestrogens presented odd profiles, depending on the formulation and concentration tested. Reference products led to the most stable and higher viability profiles across concentrations. On ex vivo permeation studies we have investigated if there were differences in performing ex vivo permeation studies using the porcine vaginal model, when collecting a proximal or a distal tissue within the vaginal tube. No extensive significant differences between these tissues were found, but the caudal vagina could be more suitable for vaginal permeation experiments since it conducted to more reproducible and consistent results. Furthermore, it was observed that drug permeation is not directly dependent on drug release from the formulation. To sum up, the conduction of this integrative preclinical assessment for vaginal semisolids can be a valuable approach in new products development or characterisation, since it could optimize cost-efficiency of new formulations development by predicting in vivo efficacy and safety profiles. In addition, these methodologies have great potential not only to be applied in cosmetics, medical devices and medicines industry, but also in academical research.
    2018-01Doctoral thesis Open access Show more
  • MM-PT study: Multimorbidity in primary care
    Publication . Prazeres, José Filipe Chaves Pereira; Santiago, Luiz Miguel de Mendonça Soares
    Chronic diseases are undeniably important as a cause of morbidity and mortality. Most of the patients with numerous chronic diseases (or chronic health problems) – multimorbidity - receive treatment in primary health care. The negative impact of multimorbidity is felt at several levels: patient (and their caregivers), general practitioner (GP), and the health system. Multimorbidity entails increasing complexity in health care (e.g. accessibility and organization of the consultation). International literature shows that it is common for people with multimorbidity to have poor health outcomes, lower quality of life, psychological distress, greater use of health services, greater complications of medical treatments, and greater health expenditure. This thesis aimed to study multimorbidity in the primary health care context in Portugal, from various perspectives (epidemiologic, patient’s and GP’s views), and explore its relevance. To achieve this general objective, the research project was divided into three Phases, specific objectives were defined (PAPER I) and it resulted in four manuscripts published in international scientific journals: 1. Determine the prevalence of multimorbidity in the adult population attending primary care in Portugal, to identify associated sociodemographic factors, and to reveal combinations of chronic health problems (PAPER II). 2. Analyse the relationship between multimorbidity, health-related quality of life, perceived family support and unmet health needs in adult patients attending primary care (PAPER III). 3. Translate the European General Practice Research Network (EGPRN) definition of multimorbidity, according to Portuguese cultural and linguistic features (PAPER IV). 4. Access GPs’ knowledge, awareness, and practices regarding multimorbidity and its management. Evaluate the clarity and usefulness of the EGPRN definition of multimorbidity. Study if providing informational material depicting results of our previous studies on multimorbidity, would change current GPs’ views on the subject (PAPER V). The first study of this thesis (PAPER II), cross-sectional and analytical, conducted from October 2013 to December 2014, across the five mainland Portugal Healthcare Administrative Regions, included 1993 individuals aged 18 and older (1279 women e 714 men), approached by their GPs (98.3% acceptance rate). Through the patient’s self-report (in-person interview), the medical records, and the GP’s knowledge of the patient’s history, information regarding clinical data and sociodemographic characteristics was collected. In the absence of a consensual definition of multimorbidity, two definitions were used: presence of two or more chronic health problems in the same individual, as well as, three or more chronic problems (from a list of 147 possible chronic health problems). In this sample of primary health care users, with a mean age of 56.3 years, 69.5% were married/cohabiting, 41.5% were pensioners/retirees, 48.7% had a low educational level and 54.4% reported a sufficient monthly income. Multimorbidity was present in 72.7% (≥2 chronic problems) and 57.2% (≥3 chronic problems) of the sample. Multimorbidity increased significantly with age. Pensioners/retirees and individuals with low levels of education were more likely to suffer from multimorbidity. Cardiometabolic and mental disorders were the most common chronic health problems. Six combinations of chronic problems were identified. The second study of this thesis (PAPER III), also cross-sectional, conducted from January 2014 to January 2015, in the Centre region of Portugal, included 521 primary health care patients aged 18 and older (334 women e 187 men) with multimorbidity (≥2 chronic health problems, of which at least one was required to be hypertension, diabetes, asthma or osteoarthritis). Through a face-to-face interview, was collected information regarding sociodemographic characteristics, clinical data, health-related quality of life (Portuguese Short Form-12 Health Status Questionnaire), family support (Portuguese Family APGAR), and unmet health needs (medical, surgical and dental care; prescription medications; mental healthcare or counselling; and eyeglasses or other technical aid). In this sample of patients, with a mean age of 58.2 years, 70.2% were married/cohabiting, 43.0% were pensioners/retirees, 57.2% had a low educational level and 46.3% reported a sufficient monthly income. Two to three chronic problems were found in 42.2%, four to five in 27.6% and six or more chronic problems in 30.1% of the patients (mean chronic health problems 4.5). Increased multimorbidity levels were linked to worse health-related quality of life, particularly the physical health. Male patients with high monthly incomes and highly functional families had better physical and mental health. High levels of education and the presence of asthma were also associated with better physical health. Contrariwise, elderly patients with high levels of multimorbidity and with osteoarthritis had lower physical health. The majority of the patients lived in highly functional families and did not have unmet health needs. When health needs were stated they were mostly for generalist medical care, dental care, and eyeglasses/other technical aid. Financial insufficiency was the primary reason for not fulfilling their health needs. In the third study of the thesis (PAPER IV), a panel of experts was assembled, consisting of 23 Portuguese GPs, who using the Delphi technique translated into Portuguese, after two rounds, the EGPRN definition of multimorbidity, with a consensus score of 8.43 out of 9: “A multimorbilidade é definida como qualquer combinação de uma doença crónica com pelo menos uma outra doença (aguda ou crónica), ou com um fator biopsicossocial (associado ou não), ou com um fator de risco somático. Qualquer fator biopsicossocial, qualquer fator de risco somático, a rede social, a carga das doenças, o consumo de cuidados de saúde e as estratégias de adaptação do doente podem funcionar como modificadores (dos efeitos da multimorbilidade). A multimorbilidade pode modificar os resultados em saúde e levar a um aumento da incapacidade, à diminuição da qualidade de vida ou à fragilidade.” The fourth and final study of this thesis (PAPER V), a web-based qualitative descriptive study, carried out in the first trimester of 2016, included 74 GPs from the districts of Coimbra and Aveiro. The sample was highly aware of multimorbidity and pointed out several difficulties and challenges in its management. Extrinsic factors were associated with the healthcare system logistics’ management (consultation time, organization of care teams, clinical information) and society (media pressure, social/family support). Intrinsic factors related to the GP, patient, and physician-patient relationship were also stated. The fundamental characteristics of family medicine were pointed out as the tools to deal with the difficulties. Also, the complex care required by multimorbid patients needs an adequate consultation time, multidisciplinary teamwork, and more education/training. The clarity and usefulness of the EGPRN definition of multimorbidity was evident, as well as the added value of disclosing to the GPs the data of the first Phases of this thesis. In conclusion, multimorbidity is a common and complex problem in primary health care in Portugal. The knowledge of its determinants and consequences, as described in this research project, may have an important role in improving the management of patients with multimorbidity. The studies of multimorbidity frequently deal with the diagnosis of medical conditions, but one should never forget that GPs also deal with the burden of a person’s suffering. Thus, one must dare to design future guidelines not just for the patient with multimorbidity, but mostly for the person with multimorbidity.
    2018-01Doctoral thesis Open access Show more
  • Mechanical performance evaluation of concrete made with recycled ceramic coarse aggregates from industrial brick waste
    Publication . Nepomuceno, Miguel; Isidoro, Rui Alberto da Silva Martins; Catarino, José Pedro Graça
    This paper describes an experimental research that aimed to evaluate the mechanical performance of concrete made with recycled ceramic coarse aggregates from industrial brick waste. Concretes incorporated natural fine aggregates (NFA), natural coarse aggregates (NCA) and the ceramic recycled coarse aggregates (RCA). The aggregates were characterized by particle size distribution, flakiness index, shape index, particle density, water absorption, loose bulk density, voids, crush resistance and resistance to fragmentation. Once the aggregates were studied, concretes were produced with RCA replacing NCA in absolute volume percentages of 0%, 10%, 30%, 50% and 75%. All the concretes were produced with the same workability and aggregate size gradation. In the hardened state, concretes were evaluated by the compressive strength, flexural strength, tensile splitting strength and density. The results showed the feasibility of partial replacement of NCA by RCA, despite the mechanical performance of concrete decreases with increasing replacement of NCA by RCA.
    2018-01Journal article Restricted access Show more
  • The impact of financing decisions of intellectual capital on firms’ financial performance and on the gap between firm’s book value and market value
    Publication . Sardo, Filipe Manuel Alves; Teixeira, Zélia Maria da Silva Serrasqueiro
    With the rise of innovation-driven era, knowledge has become the most important feature in the firm’s value creating process. Academics and practitioners have been devoting their attention to the study of intellectual capital (IC) for the last two decades. IC is an emerging and fast-evolving concept and the fact that IC is a multidisciplinary and interdisciplinary concept makes the study of this complex phenomenon challenging. In this thesis, we address several research topics, some of which still are unexplored, regarding the impact of IC on firm’s financial performance, growth opportunities and financing decisions. This investigation comprises sixth empirical studies focusing on Western European countries. The first empirical paper compiled in this Doctoral thesis is entitled “A European Empirical Study of the Relationship Between Firms' Intellectual Capital, Financial Performance and Market Value”. The purpose of this paper is two-fold: (1) to analyse the relationship between firms' IC, financial performance and market value; and (2) to analyse the relationship between ownership concentration and IC performance. Results reveal that IC is an important resource for firms' value creation and human capital is found to be a key factor of firms' wealth. Also, results indicate that ownership concentration and owners' management involvement constrain firms' IC performance. The second empirical paper is entitled “Financial Performance and Intellectual Capital: An Empirical Analysis in the Context of the Euronext Market Countries”. This paper seeks to analyse the impact of IC on financial performance, using the Value Added Intellectual Coefficient (VAIC™) method, in the European context. Results suggest that IC investments have a positive impact on firms’ financial performance in the short and long run. The human capital component is of greater importance in enhancing firms’ financial performance in both previous and current periods. Also, the results reveal that firms investing in R&D have greater financial performance, while the recent financial crisis produced a negative effect on financial performance in 2008 and 2009. The third empirical paper is entitled “Intellectual Capital and Financial Performance Considering the Crisis Period: A European Empirical Study”. The objective of this paper is to analyse the impact of the IC on the financial performance measured by Return on Assets in the European context for the period 2004-2015 as well as the global financial crisis effect on firms’ financial performance. Results indicate that IC efficiency of the current period has a positive impact on the financial performance. The three components of VAICTM Model – capital employed efficiency (CEE), human capital efficiency (HCE) and structural capital efficiency (SCE) of the current period have a positive impact on financial performance, except for SCE of that for the first group of countries has a negative impact on financial performance. Also, findings suggest that the financial crisis negatively affects financial performance on both groups of countries. The fourth empirical paper is entitled “Intellectual Capital, Growth Opportunities and Financial Performance in European Firms: Dynamic Panel Data Analysis”. The purpose of this paper is three-fold: (1) to analyse the impact of IC and growth opportunities on firms’ financial performance; (2) to analyse the moderating effect of IC on the relationship between growth opportunities and financial performance; and (3) to analyse the impact of IC on growth opportunities. Findings reveal that IC efficiency of the current period has a positive impact on firm’s financial performance of high-tech, medium-tech and low-tech European firms and results indicate the non-linearity of the relationship between growth opportunities and firm’s financial performance. Findings suggest that the positive relationship between growth opportunities and firm’s financial performance is enhanced with the efficient use of firms’ IC. Finally, results indicate that the efficient use of IC in the current period has a greater impact on growth opportunities in high-tech firms. The fifth empirical paper is entitled “Intellectual Capital and High-tech Firms’ Financing Choices in the European Context: A Panel Data Analysis” and aims to analyse the impact of IC on high-tech firms’ financing choices. Results suggest that IC investments in high-tech firms have a negative impact on debt, but a positive effect on internal finance and equity issues. High-tech firms seem to rely on equity issues to finance their activities once internal finance is exhausted, avoiding debt to finance innovative projects. High-tech firms face considerable transactions costs, given the moderated adjustment of the long-term debt ratio towards the target ratio. Low ownership concentration brings a higher diversification of financing sources. Finally, the financial crisis had a negative effect on internal finance and a positive effect on long-term debt for high-tech firms. Finally, the sixth empirical paper entitled “Intellectual Capital and Firms’ Financing Decisions in the European Context: A Panel Data Analysis” analyses the impact of IC on firms’ financing decisions, specifically if intensive IC firms follow the predictions of the main finance theories, i.e., trade-off theory (TOT) and pecking order theory (POT) in their capital structure decisions. Our findings show that IC components, such as human capital and structural capital negatively impact on firm’s book leverage in both samples of firms, while the relational capital positively impacts on book leverage in high IC efficiency firms. However, results show that the interaction between the IC components, reduce the negative impact of the human capital and structural capital on book leverage. Regarding the remaining determinants of capital structure, the findings indicate a positive effect of collaterals on book leverage, which suggests the presence of information asymmetry problems as it is the case of high IC efficiency firms that face higher costs of capital and, thereby prefer internal financing due to the lower costs. The negative relationship between profitability and book leverage suggests that both types of firms prefer to resort firstly to internal financing. The negative effect of growth opportunities on book leverage represents potential risk and, therefore, firms reduce their debt levels. The speed of adjustment of debt level towards the target debt ratio is greater in high IC efficiency firms than in low IC efficiency firms.
    2018-01Doctoral thesis Open access Show more