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  • Green logistics, reverse logistics and agro-industries: overview of scientific articles and international programs
    Publication . Miranda, João Luís; Varadinov, Maria José Pinto da Silva; Rubio Lacoba, Sergio
    One of the megatrends in the study of the supply chain is the need to incorporate “green practices” in its design and management as a demonstration of the environmental commitment of the companies. Such trend, is strongly related to the concept of Green Supply Chain Management (GSCM). GSCM aims to avoid waste of resources during the product life cycle, to ensure not only environmental sustainability but also more efficient production, taking into consideration a balance with the environment as a competitive priority that generates value added for the companies. In this way, the present book shows the results of eight investigations that have studied some issues related to the GSCM concept. The book was deleveloped under a collaborative effort between the Universidad Nacional de Colombia and other institutions such as Escola Superior de Tecnologia e Gestão, Instituto Politécnico de Portalegre (Portugal), Escuela de Ingenierías Industriales Universidad de Extremadura (Spain) and The University of Leoben (Austria).
    2014-04-21Book part Restricted access Show more
  • Study of heavy-flavor quarks produced in association with top-quark pairs at $\sqrt{s}=7$  TeV using the ATLAS detector
    Publication . ATLAS collaboration (2923 authors); Aguilar-Saavedra, Juan Antonio; Amor Dos Santos, Susana Patricia; Anjos, Nuno; Cantrill, Robert; Carvalho, João; Castro, Nuno Filipe; Conde Muiño, Patricia; Da Cunha Sargedas De Sousa, Mario Jose; Do Valle Wemans, André; Fiolhais, Miguel; Galhardo, Bruno; Gomes, Agostinho; Gonçalo, Ricardo; Jorge, Pedro; Lopes, Lourenco; Machado Miguens, Joana; Maio, Amélia; Maneira, José; Oliveira, Miguel Alfonso; Onofre, António; Palma, Alberto; Pina, João Antonio; Pinto, Belmiro; Santos, Helena; Saraiva, João; Silva, José; Veloso, Filipe; Wolters, Helmut
    Using a sample of dilepton top-quark pair ($t\bar{t}$) candidate events, a study is performed of the production of top-quark pairs together with heavy-flavor (HF) quarks, the sum of $t\bar{t}+b+X$ and $t\bar{t}$+c+X, collectively referred to as $t\bar{t}$ + HF. The data set used corresponds to an integrated luminosity of 4.7  $fb{−1}$ of proton-proton collisions at a center-of-mass energy of 7 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. The presence of additional HF (b or c) quarks in the $t\bar{t}$ sample is inferred by looking for events with at least three b-tagged jets, where two are attributed to the b quarks from the $t\bar{t}$ decays and the third to additional HF production. The dominant background to $t\bar{t}$ + HF in this sample is $t\bar{t}$+jet events in which a light-flavor jet is misidentified as a heavy-flavor jet. To determine the heavy- and light-flavor content of the additional b-tagged jets, a fit to the vertex mass distribution of b-tagged jets in the sample is performed. The result of the fit shows that 79 ± 14 (stat) ± 22 (syst) of the 105 selected extra b-tagged jets originate from HF quarks, 3 standard deviations away from the hypothesis of zero $t\bar{t}$+ HF production. The result for extra HF production is quoted as a ratio (RHF) of the cross section for $t\bar{t}$ + HF production to the cross section for $t\bar{t}$ production with at least one additional jet. Both cross sections are measured in a fiducial kinematic region within the ATLAS acceptance. RHF is measured to be [6.2±1.1(stat)±1.8(syst)]% for jets with $p_T$ > 25  GeV and |η| < 2.5, in agreement with the expectations from Monte Carlo generators.
    2014-04-21Journal article Open access Show more
  • O desempenho dos fundos de investimento em tempos de crise: o caso Português, 2005-2010
    Publication . Alves Mendes, Marco Paulo; Cabrito, Belmiro
    Esta dissertação de mestrado aborda a evolução dos modelos financeiros, começando no modelo de Markowitz e terminando no modelo Arbitrage Pricing Theory. Entre ambos foram debatidos outros modelos como o Capital Asset Pricing Model. Depois de debatidos os modelos foram explicadas as medidas de desempenho global, mais concretamente, o Rácio de Sharpe, entre outros. Finalmente discutira-se o conceito de crise financeira, os diversos tipos de crise e alguns dos indicadores que permitem perceber a existência de uma crise. Esta investigação utilizou como metodologia o paradigma qualitativo, adaptado a esta dissertação em concreto e pretendia perceber se o comportamento de fundos de investimento permite antecipar uma crise financeira. As técnicas utilizadas foram a pesquisa bibliográfica, a pesquisa de dados e a entrevista. Os dados recolhidos complementam-se entre si. Foi recolhida uma amostra de fundos de investimentos mobiliários de forma a medir e analisar a sua performance, para esta análise recorreu-se á obtenção de dados quantitativos. Estes dados foram discutidos à luz do discurso dos dois interlocutores privilegiados se entrevistou. Terminou com algumas conclusões sendo de destacar o facto de que crise financeira atual afetou o desempenho dos fundos de investimento estudados e que esta crise se fez sentir particularmente em 2008
    2014-04-21Master thesis Open access Show more