Ferreira P.,University of Évora |
Ferreira P.,Polytechnic Institute of Portalegre
Physica A: Statistical Mechanics and its Applications | Year: 2016
The objective of this paper is to analyze if the Euro crisis, which started in 2009, changes the cross-correlation pattern of bank shares with the national stock indexes in both in Eurozone and non-Eurozone countries. We study all banks listed in the main stock indexes of European Union countries, applying the detrended cross-correlation coefficient. An increase in the correlation indicates that the banking sector now has a greater influence in the national index, while a decrease in the correlation means the opposite. Our results show that 19 of the 39 banks analyzed in the Eurozone increased their correlation with national indexes, whilst in the non-Eurozone countries this happened with 14 of the 24 studied banks. While some authors argue that the crisis may have been aggravated by the weight of banks in the economy, Eurozone policy makers should pay attention to this feature. © 2016 Elsevier B.V.
Brito P.S.D.,Polytechnic Institute of Portalegre |
Patricio S.,Polytechnic Institute of Portalegre |
Rodrigues L.F.,Polytechnic Institute of Portalegre |
Sequeira C.A.C.,University of Lisbon
Surface and Coatings Technology | Year: 2012
The recovery of metallic ions by electrodeposition from solutions resulting from lixiviation of spent Zn-MnO 2 batteries was studied in an attempt to optimize the electrodeposition process, selectivity of ion-separation, morphologic characteristics and anticorrosive and galvanic properties of metallic deposits. The simultaneous deposition of zinc and manganese on different ferrous substrates under various experimental conditions was tested to access the efficiency of the electrodeposition, the morphology and composition of metallic deposits as well as their performance as galvanic coating layers. The effect of additives, namely, boric acid and methylamine, on the properties of produced covering layers was also studied. Results show that solutions resulting from hydrometallurgical treatment of spent domestic Zn-MnO 2-batteries can be processed directly as electrodeposition baths for the recovery of zinc alloys. The presence of additives, such as boric acid and methylamine, with buffering or passivating effects, does improve the simultaneous deposition of Mn. © 2011 Elsevier B.V.
Francisco S.M.,University of Lisbon |
Veiga Simao A.M.,University of Lisbon |
Ferreira P.C.,University of Lisbon |
Martins M.J.D.D.,Polytechnic Institute of Portalegre
Computers in Human Behavior | Year: 2015
The purpose of this study was to investigate how university students perceive their involvement in the cyberbullying phenomenon, and its impact on their well-being. Thus, this study presents a preliminary approach of how college students' perceived involvement in acts of cyberbullying can be measured. Firstly, Exploratory Factor Analysis (N = 349) revealed a unidimensional structure of the four scales included in the Cyberbullying Inventory for College Students. Then, Item Response Theory (N = 170) was used to analyze the unidimensionality of each scale and the interactions between participants and items. Results revealed good item reliability and Cronbach's α for each scale. Results also showed the potential of the instrument and how college students underrated their involvement in acts of cyberbullying. Additionally, aggression types, coping strategies and sources of help to deal with cyberbullying were identified and discussed. Lastly, age, gender and course-related issues were considered in the analysis. Implications for researchers and practitioners are discussed. © 2014 Elsevier Ltd. All rights reserved.
Nunes P.M.,University of Beira Interior |
Nunes P.M.,University of Évora |
Serrasqueiro Z.,University of Beira Interior |
Serrasqueiro Z.,University of Évora |
Leitao J.,Polytechnic Institute of Portalegre
Research Policy | Year: 2012
To investigate whether there is a similar relationship between R&D intensity and growth in high-tech and non-high-tech small and medium-sized enterprises (SMEs), we examine two samples of SMEs in manufacturing industries, applying the two-step estimation method. Our findings are that R&D intensity restricts the growth of high-tech SMEs at lower levels of R&D intensity and stimulates their growth at higher levels. However, R&D intensity restricts the growth of non-high-tech SMEs regardless of the level of R&D. The relationships obtained between other determinants considered in the literature and the growth of high-tech and non-high-tech SMEs allow us to conclude that (i) smaller, younger, non-high-tech SMEs grow more quickly than larger, older, non-high-tech SMEs, which does not occur in the case of high-tech SMEs; and (ii) financing restrictions are especially important in financing the growth of high-tech SMEs, compared with non-high-tech SMEs. © 2011 Elsevier B.V. All rights reserved.
Oliveira J.F.,Polytechnic Institute of Portalegre
2013 8th International Conference on Information Technology in Asia - Smart Devices Trend: Technologising Future Lifestyle, Proceedings of CITA 2013 | Year: 2013
In an ideal world, blind people could navigate any new route without training, travel by underground/metro during rush hour without problems, and explore with confidence. Environments can be diverse and dynamic and unfortunately no universal gadget-aid solution yet exists to help navigation. Advances in mobile phone technology and entertainment devices such as the Kinect are allowing for new application scenarios to arise. In this paper, a system that could help interface a person to a wide range of environments is presented. The Path Force Feedback Belt system takes at a fixed rate dual images of the environment using a mobile device, it reconstructs a 3D model of the surroundings, and extracts features such as sidewalk corners, walls, and obstacles. The mobile device then determines which of the force feedback actuators on a 360° belt worn on the waist has to be signaled, hence providing path feedback. © 2013 IEEE.
Lourinho G.,Polytechnic Institute of Portalegre |
Brito P.,Polytechnic Institute of Portalegre
Reviews in Environmental Science and Biotechnology | Year: 2015
Biodiesel, i.e. a mixture of monoalkyl esters of long chain fatty acids derived from renewable biological sources such as vegetable oils has in recent years emerged as an alternative fuel for transportation sector. The conventional method of producing biodiesel is through homogeneous catalytic transesterification; however, increased production costs associated with downstream purification steps have led to the development of more cost-effective and environmental friendly technologies. These advanced production technologies involve heterogeneous or enzymatic catalysts to produce biodiesel, as well as no catalysts in supercritical conditions. Heterogeneous catalytic systems can ease the separation of biodiesel from the reaction mixture along with the possibility of catalyst recovery, potentially leading to lower production costs; enzymatic catalysts give the same advantages, but transesterification can be carried out in milder conditions and with a wider range of feedstocks. Biodiesel synthesis in supercritical conditions composes another alternative to conventional methods due to higher reaction rates, shorter reaction times, and simpler biodiesel separation steps. Nevertheless, mass transfer limitations caused by diffusion problems between phases represent an hindrance for future establishment of these technologies, calling for the development of novel methods to intensify the process. These process intensification technologies include ultrasound irradiation, microwave heating, use of co-solvents, and membrane reactors. The main focus of this review is to discuss recent advances as regards to biodiesel production technologies, devoting a special attention to the use of novel catalysts, diversified feedstocks, besides an analysis of main operational parameters of transesterification processes. © 2014, Springer Science+Business Media Dordrecht.
Loures L.,Polytechnic Institute of Portalegre |
Loures L.,Center for Spatial and Organizational Dynamics
Habitat International | Year: 2015
Generally located in advantageous locations near city centers or along waterfronts and supported by existing infrastructure, post-industrial landscapes constitute environmentally impaired resources that need to be returned to productive uses, and reintegrated into the surrounding community. However, the complexity of any post-industrial redevelopment project, evident in the number of different ways in which it is described both in the literature and by designers and developers who work and/or analyze these landscapes make post-industrial redevelopment difficult to accomplish. Considering the purpose of the present research, it was necessary to use several methods throughout the investigation, including quantitative and qualitative research methods divided in two main sections: literature review and case study research. Considering the collected data and the performed statistical analysis, it is possible to conclude that, thought there are strong relationships between several of the identified benefits and barriers, the survey revealed distinct perceptions about the benefits and the barriers associated to post-industrial redevelopment between the general public (i.e. redeveloped post-industrial site users) and redevelopment experts, idea which is of utmost importance considering that designers tend to be primarily focused on aesthetics, leaving society's other main goals to secondary status, and that planning and landscape redevelopment activities are increasingly becoming less the result of design and more the expression of economic and sociocultural forces. Moreover the performed analysis showed that while for the general public the main barriers to post-industrial redevelopment are the potential for biological, physical and chemical impacts, and the uncertainty about liability and cleanup issues; for experts the main barriers are the high redevelopment costs; and the challenges in obtaining financial support. Regarding the main benefits while for the general public, the creation of open green spaces and the creation of jobs are the most important ones, for experts they are associated with the possibility to reduce urban sprawl, and encourage recreation and connectivity. © 2014 Elsevier Ltd.
De Miranda J.L.,Polytechnic Institute of Portalegre
CSEDU 2010 - 2nd International Conference on Computer Supported Education, Proceedings | Year: 2010
In a Management Science MSc. course, we use a computer-aided approach to conjugate multivariate analysis with decision support through optimization tools. The targeted decision support is based on a methodology that relies on specific problems built to promote learning. The optimality of discrete decisions on uncertain environment is aimed, they are applied computational tools onto multivariate analysis and optimization frameworks and these tools support the development of decision rules. Case problems specifically built are focused, as investments programming, financial risk treatment, or supply chain planning and distribution activities, on a Problem Based Learning (PBL) approach. This PBL methodology is embedded on a context where we simulate enterprise computer-aided activities and this immersive approach is encapsulated by a blended learning framework. Considering the intensive schedule that is defined to cope with the student-workers availability, this approach avoids some dislike related to long lectures of quantitative kind, which can reach eight hours in continuum.
Calha A.,Polytechnic Institute of Portalegre
Saude e Sociedade | Year: 2015
The extended increasing of life expectancy associated with a significant decline in the birth rate have contributed to a rapid aging of societies and a profound change in the demographic structure of many European countries. We analyze in this article the specific condition of the senior in the countries of Southern Europe and Scandinavia. In the case of countries with a configuration of different models of social protection, we realize that there are different ways of living old age in these societies. For this reason, our analysis uses the results obtained in the European Social Survey (round 5-2010). The analysis reveals the existence of different models that set the senior condition in the referred societies, which means different ways of dealing with the aging process. To conclude, the condition of the elderly does not depend solely on biological factors related to physical limitation, it is also influenced by social configuration that fits the experience of this period of individual life, as well as the way old people face it. © 2015 UNIV SAOPAULO. All rights reserved.
Lourinho G.,Polytechnic Institute of Portalegre |
Brito P.,Polytechnic Institute of Portalegre
Energy | Year: 2015
This work focuses on assessing the potential for generation of biomass residues from agroforestry sources in a region of Portugal (Alto Alentejo), within the scope of energy valorization of the biomass by means of combustion technologies. The model uses a GIS-based method to estimate the technical potential of biomass based on current cartographic and statistical data. The analyzed components related to the biomass potential are: effective biomass area (in ha), biomass availability (in dry t/year) and energy potential (in GJ/year). The potential of agricultural and forest residues in Alto Alentejo is estimated to be 4000 dry t/year and 40,000 dry t/year, respectively. This amount of biomass corresponds to an energy potential of 158,000GJ/year, which is equivalent to 100% of the combined consumption of electricity in three out of the nine municipalities covered in this study. A preliminary analysis on the suitability of the location and characteristics of a 9MW biomass power plant in the region is made; alternative solutions and most representative species are also discussed. It was concluded that not enough biomass is available to supply the energy facility and that the most promising option for the region is the combustion of residues in small scale units. © 2014 Elsevier Ltd.