Neural substrates supporting the influence of working memory contents on visual attention

The present thesis investigates the neural mechanisms supporting working memory (WM) guidance of visual attention, focusing on the role of the thalamus. Chapter 1 is a review of the relevant literature and sets-up the specific research aims. Chapters 2 and 3 explore the role of the thalamus on guidance of attention by WM contents. Stroke patients with focal-brain lesions performed a WM-guided search task. In valid conditions, the colour of the search target was pre-cued by the WM cue while on neutral conditions there was no cue prior to search. In invalid conditions, the WM cue specified the colour of a search distracter and the target appeared elsewhere. First, it was hypothesized that lesions to the thalamus could lead to deficits in attentional control (e.g. failing to separate irrelevant memory contents with relevant target information and leading to increased capture from WM-like distracters during invalid search conditions). An alternative hypothesis was that the thalamus may support the capture of attention by WM contents, hence thalamic patients would display little bias of attention from the WM contents, despite those contents are being maintained in memory. It was found that patients with focal-thalamic lesions especially in the ventrolateral nucleus, showed no search benefit from the valid cues on search as opposed to a control group of patients with lesions outside the thalamus and non-stroke patients. In the invalid condition, thalamic patients showed no capture by the irrelevant search item that matched the WM cue, whereas a group of healthy age-match controls exhibited the normal effect of capture by irrelevant contents held in WM. These observations suggest that lesions to the ventrolateral nucleus of the thalamus impair the capture of attention from WM contents. In Chapter 4, I aimed to establish the role of cortical structures that are known to be structurally connected with the ventrolateral nucleus of the thalamus (i.e. superior frontal gyrus) in WM guidance of attention. To do this, I investigated the effects of transcranial direct current stimulation (tDCS) of the dorsal frontal cortex in WM guidance of attention under distinct WM loads. I found that despite the effect of WM guidance of attention decreasing as WM load increased, frontal-tDCS modulated WM guidance in these conditions. We suggest that the dorsal frontal cortex forms part of a network alongside the thalamus in supporting WM guidance of attention. Finally, I conducted a functional Magnetic Resonance Imaging (fMRI) experiment (Chapter 5) with healthy volunteers to test the hypothesis that the thalamus plays a role in WM guidance when learning of abstract cue-target feature associations needs to take place for guidance of behaviour to emerge. I used four Japanese ideograms as WM cues, each associated with the colour surrounding the sought after target in the subsequent search display (valid trials). In the neutral condition, four different Japanese ideograms were presented that did not predict the colour of the target. Hence, for WM to guide attention the association between the abstract cue and the colour that surrounded the search target needed to be learned. I found that responses in the thalamus and the frontoparietal cortex displayed sensitivity to the predictiveness of the ideogram cues as WM guidance of attention emerged during learning. The findings reported in this thesis demonstrate the pivotal role of the thalamus in WM guidance of attention.Open Acces

Competitividade e incumprimento das funções de gestão da construção

De um modo geral, a problemática da falta de competitividade do sector da construção em Portugal preocupa os vários intervenientes e tem sido objecto da atenção dos sucessivos Governos, órgãos de soberania, parceiros sociais, meios de comunicação social, investigadores nacionais e estrangeiros, etc. Os elementos chave de avaliação da competitividade têm vindo a ser objecto de estudo e pesquisa internacional, sendo que ao nível das obras, releva a falta de cumprimento das principais funções de gestão nos empreendimentos de construção. Não obstante ser reconhecido por todos os intervenientes o fraco desempenho desses indicadores de gestão, sendo situações comuns as derrapagens orçamentais, os atrasos na conclusão das obras, a insuficiente qualidade do produto final e a manifesta falta segurança no trabalho, não existe uma quantificação objectiva destes incumprimentos, nem as razões concretas para que tal aconteça. Neste trabalho apresentam-se os resultados de um inquérito a Donos de Obra e Empreiteiros em relação ás dimensões e às causas dos incumprimentos das principais funções de gestão na construção, no que toca a obras públicas concluídas nos últimos anos, relacionando-as com a falta de competitividade da indústria da construção em Portugal.Fundação para a Ciência e aTecnologia (FCT) -projecto SAPIENS nº 4762

Managing stakeholders conflicts

It is not unusual that a chapter on conflict management, which is about, generally speaking, helping people or organizations that are in conflict with each other to deal with their differences, opens up with this statement (Moore, 1986 cited in Gordon, 1966): All societies, communities, organizations, and interpersonal relationships experience conflict at one time or another in the process of day-to-day interaction. Conflict is not necessarily bad, abnormal, or dysfunctional; it is a fact of life.The author, Alexandre Ferreira da Silva, is supported by Portuguese Foundation for Science and Technology (SFRH/BD/39459/2007)

Claims in railway projects in Portugal

Comunicação apresentada na CIB W102-2005, Lisboa, Portugal, 18 - 20 Maio 2005.The importance of claims and disputes in Portuguese public contracting is so large nowadays that most construction managers tend to consider a specific final stage of the project life cycle for dealing with them. The aim of this paper is to characterise claims in railway projects conducted in the last few years in Portugal. A survey was made to project promoters and data from a number of projects has been collected and classified according to usual claim causes as currently adopted in literature. The results of the survey show that project changes and delays contribute to roughly 99% of the claims surveyed

Why can’t main project management functions be achieved in most construction projects?

The lack of accomplishment of the main management functions in construction projects had been reported worlwide. The symptoms are well recognized, like cost and time overruns, deficient quality and lack of safety. To help clarifying the reasons for this evidence, a survey was carried to Portuguese construction stakeholders, based on an Internet inquiry, aimed to characterize past projects. While time for the answers is still running, the main important conclusion retrieved from the survey is that industry practicioners do not have, or do not want to provide, quantitative information about past projects. This, in fact, may be signalled as the first reason for the lack of competitiveness of the construction industry in Portugal

Oil-growth nexus in oil producing countries: macro panel evidence

The oil consumption-economic growth nexus is examined in a panel of oil producing countries over a long time span (1965-2012). Both, the ratio of oil production to primary energy consumption, i.e. oil self-sufficiency, and the persistence of the second structural oil shock were controlled for. The phenomenon of cross-sectional dependence that is present in the panel confirms that these countries share common spatial patterns, unobserved common factors, or both. The cointegration/long memory relationships as well as the panel data estimators’ appropriateness are analysed and discussed. A dynamic Driscoll-Kraay estimator, with fixed effects, was shown to be adequate to cope with the phenomena of heteroskedasticity, contemporaneous correlation, first order autocorrelation and cross-sectional dependence present in the panel. The results are consistent with the growth hypothesis, i.e. that oil consumption proves be a driver of economic growth. The second structural oil break (1979), reveals the long-lasting positive effect exerted by oil consumption on growth. The ratio of oil production to primary energy consumption has exerted a positive impact on growth. Thus, policymakers should take into account the benefits of promoting oil self-sufficiency, by reinforcing the use of endogenous resourcesinfo:eu-repo/semantics/publishedVersio

TNA4OptFlux : a software tool for the analysis of strain optimization strategies

BACKGROUND:Rational approaches for Metabolic Engineering (ME) deal with the identification of modifications that improve the microbes' production capabilities of target compounds. One of the major challenges created by strain optimization algorithms used in these ME problems is the interpretation of the changes that lead to a given overproduction. Often, a single gene knockout induces changes in the fluxes of several reactions, as compared with the wild-type, and it is therefore difficult to evaluate the physiological differences of the in silico mutant. This is aggravated by the fact that genome-scale models per se are difficult to visualize, given the high number of reactions and metabolites involved.FINDINGS:We introduce a software tool, the Topological Network Analysis for OptFlux (TNA4OptFlux), a plug-in which adds to the open-source ME platform OptFlux the capability of creating and performing topological analysis over metabolic networks. One of the tool's major advantages is the possibility of using these tools in the analysis and comparison of simulated phenotypes, namely those coming from the results of strain optimization algorithms. We illustrate the capabilities of the tool by using it to aid the interpretation of two E. coli strains designed in OptFlux for the overproduction of succinate and glycine.CONCLUSIONS:Besides adding new functionalities to the OptFlux software tool regarding topological analysis, TNA4OptFlux methods greatly facilitate the interpretation of non-intuitive ME strategies by automating the comparison between perturbed and non-perturbed metabolic networks. The plug-in is available on the web site http://www.optflux.org webcite, together with extensive documentation.This work is funded by ERDF - European Regional Development Fund through the COMPETE Programme (operational programme for competitiveness) and by National Funds through the FCT (Portuguese Foundation for Science and Technology) within projects ref. COMPETE FCOMP-01-0124-FEDER-015079 and PEst-OE/EEI/UI0752/2011. JPP and RP work is funded by PhD grants from the Portuguese FCT (ref. SFRH/BD/41763/ 2007 and SFRH/BD/51111/2010)

Co-designed FreeRTOS deployed on FPGA

Most embedded systems are bound to real-time constraints. Two of the critical metrics presented in these systems are determinism and latency. Due to growing in complexity of embedded applications, real time operating systems (RTOS) are needed, not only to hide the increasingly complex hardware, but also to provide services to the system’s running tasks. Unfortunately, this new layer on an embedded system puts more pressure on the aforementioned metrics. One of the ways to cope with this problem is to offload RTOS run-time services to the hardware layer. This paper presents a hybrid hardware/software implementation of this technique upon the well known FreeRTOS, improving system’s latency and predictability, by migrating critical runtime services to hardware. The developed hardware accelerators were synthesized on a field-programmable gate array (FPGA), exploiting the point-to-point bus Fast Simplex Link (FSL) to interconnect to the Xilinx’s Microbaze soft-core processor.This work has been supported by FCT - Foundation for Science and Technology within the Project Scope: PEst-OE/EEI/UI0319/2014

Detecção automática de estruturas anatómicas em imagens digitais da retina

Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 201