Browsing by Issue Date, starting with "2017-10"
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- The value relevance of GRI reports in the Portuguese stock marketPublication . Arraiano, Irene Guia; Miralles-Quirós, Maria del MarSocially Responsible Investment has grown enormously and the publication of reports has increased in developed economies in recent years. The fact that this type of reporting is on a voluntary basis in several countries raises questions about whether stock markets investors would take these reports into consideration. This study attempts to address this question, drawing on a sample of 46 firms listed on the Portuguese stock market over the 2005-2015 period. To that end, we construct a portfolio selecting the socially responsible firms rated by Global Reporting Initiative (GRI) annual reports and consider the market portfolio as a benchmark. We analyse the risk-adjusted returns and systematic risk sensibilities of these firms applying the classical market model. For robustness, a spanning test is realized. Our results support that the investment in socially responsible firms in the Portuguese stock market leads to higher returns assuming less systematic risk. These results are important for investors as well as academics.
- Locality-aware GC optimisations for big data workloadsPublication . Patrício, Duarte; Bruno, Rodrigo; Simão, José; Ferreira, Paulo; Veiga, LuísMany Big Data analytics and IoT scenarios rely on fast and non-relational storage (NoSQL) to help processing massive amounts of data. In addition, managed runtimes (e.g. JVM) are now widely used to support the execution of these NoSQL storage solutions, particularly when dealing with Big Data key-value store-driven applications. The benefits of such runtimes can however be limited by automatic memory management, i.e., Garbage Collection (GC), which does not consider object locality, resulting in objects that point to each other being dispersed in memory. In the long run this may break the service-level of applications due to extra page faults and degradation of locality on system-level memory caches. We propose, LAG1 (short for Locality-Aware G1), na extension of modern heap layouts to promote locality between groups of related objects. This is done with no previous application profiling and in a way that is transparent to the programmer, without requiring changes to existing code. The heap layout and algorithmic extensions are implemented on top of the Garbage First (G1) garbage collector (the new by-default collector) of the HotSpot JVM. Using the YCSB benchmarking tool to benchmark HBase, a well-known and widely used Big Data application, we show negligible overhead in frequent operations such as the allocation of new objects, and significant improvements when accessing data, supported by higher hits in system-level memory structures.
- Assessment of staphylococcus aureus colonization in bakery workers: a case studyPublication . Ribeiro, Edna; Clérigo, AnáliaIntroduction - The World Health Organization (WHO) describes antimicrobial resistance in human pathogens as a global health challenge. In the context of food handlers, although human colonization with bacteria such as s. aureus is associated high risk to transfer the infection to others, or contaminate foods and food surfaces during handling, information regarding bacteria bioburden is still scarce. Considering that s. aureus is a cause of staphylococcal food poisoning (SFP), resultant from ingestion of staphylococcal enterotoxins present in food, is one of the most prevalent foodborne intoxications in the world, with fatality rates particularly concerning for children and the elderly and that foodstuff contamination by colonized food handlers represent a major risk for SFP, the assessment of colonization of these workers is crucial. Aim of study - Considering that food contamination by colonized food handlers represent a major risk for SFP, here we aim to assess s. aureus colonization prevalence of both sensible and resistant strains in a bakery as a case study.
- An exploratory approach to capture interpersonal synergies between defenders in footballPublication . Milho, J.; Passos, P.Collective behaviors in football may result from players forming inter¬personal synergies that contribute to performance goals. Due to the huge number of variables that continuously constrain players’ behavior during a game, the way that these synergies are formed remain unclear. In team sports such as football, a common effective defensive tactical strategy is one in that defending players “fill” the space between themselves, disturbing the attackers intentions to get closer to the goal and score. To assemble such situations, we hypothesized that the defenders create a functional synergy, which occurs when components of a system behave as a whole contributing to the development of a specific task (Kelso, 2009). Supported on a previous research in Rugby Union (Passos et al., 2017), we postulate that synergies are—mechanisms that substantiate interpersonal coordination in team sports of Football. It is relevant to state that a general feature of coordination is the mutual dependency among system components (e.g., defenders), which led them to behave (e.g., play) as a whole (Kugler and Turvey, 1987; Kelso, 2009). The creation of a synergy is grounded on a comple¬mentarity between variability and stability, which means that some defending player’s (as components of a system) must vary the manner they interact to stabilize specific performance variables (Black et al., 2007; Passos et al., 2017). On this exploratory study, our aim was to quantify interpersonal synergies in team sport of football, in particular, to quantify dyadic interpersonal synergies between the four field defenders that formed the defensive squad of a football team. We hypothesized that neighboring defending players adjust their relative positions to stabilize an interpersonal distance and as such create interpersonal synergies.
- Influência da temperatura de fixação na análise de DNA in vitro: revisãoPublication . Rego, Beatriz; Duarte, Cláudia; Canhoto, Inês; Marques-Ramos, AnaIntrodução: Uma vez que os tecidos fixados em formalina e impregnados em parafina (FFIP) fazem parte da rotina laboratorial em histopatologia, existindo em grande número, estes constituem uma fonte importante de material biológico para estudos moleculares. O DNA extraído destes tecidos pode, no entanto, encontrar-se degradado, sendo a fixação uma das etapas em que a degradação poderá ocorrer. Isto irá depender de vários fatores, como o tipo de fixador, o seu pH, tempo e temperatura de fixação. Uma vez que existe uma crescente necessidade de DNA para a realização de técnicas moleculares, úteis para a caraterização de mutações em tumores e escolha de terapêuticas mais eficazes, vários autores têm tes-tado os efeitos da fixação na qualidade do DNA extraído, nomeadamente da temperatura. Nesta revisão, iremos procurar compreender se existe uma temperatura ideal de fixação para tecidos FFIP quando se pretendem realizar técnicas de análise de DNA in vitro. Objetivos do estudo: 1) Sistematizar os estudos existentes sobre a influência da temperatura de fixação no DNA extraído de tecidos fixados em formalina e impregnados em parafina; 2) Verificar a existência de um consenso sobre qual a temperatura de fixação ideal para a obtenção de melhores resultados na análise de DNA in vitro.
- Microwave-assisted peroxidative oxidation of toluene and 1-phenylethanol with monomeric keto and polymeric enol aroylhydrazone Cu(II) complexesPublication . Sutradhar, Manas; Alegria, Elisabete; Roy Barman, Tannistha; Scorcelletti, Francesco; Guedes Da Silva, M. Fátima C.; Fatima, C.; Pombeiro, ArmandoCu(II) complexes in two different tautomeric forms (keto and enol) derived from the aroylhydrazone Schiff base 2-hydroxy(2-hydroxybenzylidene)benzohydrazide (H2L) have been synthesized and characterized by elemental analysis, IR spectroscopy, ESI-MS and single crystal X-ray crystallography. While the compound with the enol form of the ligand exists as the 1D polymer [Cu(kappa KNOO',2 kappa O',3 kappa O"-L)](n) (1), that with the keto form of the ligand occurs as the monomer [Cu(KNOO'-HL)CI(CH3OH)] (2). Both complexes act as good catalysts for the microwave-assisted peroxidative oxidation of toluene and 1-phenylethanol with tert-butyl hydroperoxide. Complex 2 exhibits the highest activity in both reactions, leading selectively to,a maximum product yield of 39 and 92%, respectively.
- Fungal contaminants: a paradoxal void in safety regulation of drinking water and recreational areasPublication . Brandão, J. C.; Sabino, Raquel; Novak-Babic, M.; Gunde-Cimerman, N.; Veríssimo, Carla; Viegas, Carla; Vargha, M.; Meyer, W.Objectives: The United Nations sustainable development goal #3, aims to “By 2030, substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contamination” (New York, September 2015). This study’s objective is to assess the European drinking and bathing water regulations and detect missing fungal parameters that may affect human health.
- Ruído ocupacional em Portugal – periodicidade das medições e da avaliação de riscosPublication . Gomes, Virgínia C.; César, CarlosIt is been over a decade since the transposition into the portuguese legislation (Decreto-Lei nº 182/2006, de 6 de Setembro1) of theEuropean Directive on the minimum health and safety requirements regarding the exposure of workers to the risks arising from noise. However,questionsstill remain concerning the frequency with which the appropriate occupational noise measurements should be carried out. In this paper, the authors present a review of the periodicity criteria for theoccupational noise measurements, concluding on its influence on thesubsequent risk assessment results. Já passou mais de uma década desde a transposição para a legislação portuguesa (Decreto- Lei nº 182/2006, de 6 de Setembro1) da Directiva Europeia relativa às prescrições mínimas de segurança e de saúde em matéria de exposição dos trabalhadores aos riscos devidos ao ruído. Contudo, continuam a subsistir dúvidas relativamente à periodicidade com que as adequadas medições de ruído ocupacional devem ser efectuadas. Neste artigo, os autores apresentam uma revisão dos critérios inerentes à periodicidade da realização das medições de ruído ocupacional, concluindo sobre a influência da mesma nos resultados da subsequente avaliação de riscos.
- Crustal seismic structure beneath Portugal and southern Galicia (Western Iberia) and the role of Variscan inheritancePublication . Veludo, Idalina; Dias, Nuno; Fonseca, Paulo E.; Matias, Luís; Carrilho, Fernando; Haberland, Christian; Villasenor, AntónioThe crustal structure in Western Iberia, is the result of a complex geodynamic history. Most of the surface is covered by rocks dating to the Variscan orogeny, the coastal ranges dominated by Mesozoic structures and Mesocenozoic basins covering partially the mainland. In this study we present the results of a local earthquake tomographic study, performed to image in depth this complex crustal structure down to 24 km depth.& para;& para;The obtained tomograms present a good correlation with the surface geology, in general with higher Vp velocities in the north, and lower Vp velocities in the south. The heterogeneity observed on the surface geology of the Galicia-Tras-os-Montes Zone is well marked, being a relatively thin layer over the smoother structure of the Centro Iberia Zone CIZ. The CIZ crustal block confined between the Porto-Tomar-Ferreira do Alentejo and the Manteigas-Braganqa faults having higher Vp values, enhancing the contrast to the Lusitanian Basin to the west. The Ossa-Morena Zone corresponds to the unit presenting the greater heterogeneity in both Vp and Vp/Vs models, showing also with a complex transition to the South Portuguese Zone and a relatively smooth transition to the Centro Iberian Zone. Unexpectedly, the South Portuguese Zone present an east-west velocity variation with no apparent correspondence with the surface geology. The transition to the coastal Mesocenozoic basins is clearly marked, the Lower Tagus Valley corresponding to a similar to 4 km thick low velocity region.& para;& para;The relocation inland recorded seismicity in the period 2000-2014 allows cleansing some of the alignments and establish their correlation with some of the active structures in Portugal. The model features and seismicity pattern reveal the strong role played by the Variscan heritage.
- SmartGC: online memory management prediction for PaaS Cloud ModelsPublication . Simão, José; Esteves, Sérgio; Veiga, LuísIn Platform-as-a-Service clouds (public and private) an efficient resource management of several managed runtimes involves limiting the heap size of some VMs so that extra memory can be assigned to higher priority workloads. However, this should not be done in an application-oblivious way because performance degradation must be minimized. Also, each tenant tends to repeat the execution of applications with similar memory-usage patterns, giving opportunity to reuse parameters known to work well for a given workload. This paper presents SmartGC, a system to determine, at runtime, the best values for critical heap management parameters of JVMs. SmartGC comprises two main phases: (1) a training phase where it collects, with different heap resizing policies, representative execution metrics during the lifespan of a workload; and (2) an execution phase where it matches the execution parameters of new workloads against those of already seen workloads, and enforces the best heap resizing policy. Distinctly from other works, this is done without a previous analysis of unknown workloads. Using representative applications, we show that our approach can lead to memory savings, even when compared with a state-of-the-art virtual machine - OpenJDK. Furthermore, we show that we can predict with high accuracy the best heap policy in a relatively short period of time and with a negligible runtime overhead. Although we focus on the heap resizing, this same approach could also be used to adapt other parameters or even the GC algorithm.