Stochastic group selection model for the evolution of altruism

We study numerically and analytically a stochastic group selection model in which a population of asexually reproducing individuals, each of which can be either altruist or non-altruist, is subdivided into $M$ reproductively isolated groups (demes) of size $N$. The cost associated with being altruistic is modelled by assigning the fitness $1- \tau$, with $\tau \in [0,1]$, to the altruists and the fitness 1 to the non-altruists. In the case that the altruistic disadvantage $\tau$ is not too large, we show that the finite $M$ fluctuations are small and practically do not alter the deterministic results obtained for $M \to \infty$. However, for large $\tau$ these fluctuations greatly increase the instability of the altruistic demes to mutations. These results may be relevant to the dynamics of parasite-host systems and, in particular, to explain the importance of mutation in the evolution of parasite virulence.Comment: 12 pages, 7 figure

Use of software in learning difficulties of reading: comparative analysis between digital environment and hybrid environment

The learning difficulties of the letter-sound relations are seen as a risk factor for future difficulties in learning to read. Ideally, the identification of children at risk of failure to learn reading and writing should occur in the last year of pre-school or early in the first year, so that intentional programs can be implemented to promote basic reading skills. The most promising reading learning support programs combine explicit phonological awareness training with highly structured reading instruction. This study evaluated the impact of two early intervention programs on reading learning difficulties. A program exclusively in virtual environment and a hybrid program, comprising sessions in virtual environment and in real environment.info:eu-repo/semantics/publishedVersio

A sufficient optimality condition for delayed state-linear optimal control problems

We give answer to an open question by proving a sufficient optimality condition for state-linear optimal control problems with time delays in state and control variables. In the proof of our main result, we transform a delayed state-linear optimal control problem to an equivalent non-delayed problem. This allows us to use a well-known theorem that ensures a sufficient optimality condition for non-delayed state-linear optimal control problems. An example is given in order to illustrate the obtained result.Comment: This is a preprint of a paper whose final and definite form is with 'Discrete and Continuous Dynamical Systems -- Series B' (DCDS-B), ISSN 1531-3492, eISSN 1553-524X, available at [http://www.aimsciences.org/journal/1531-3492]. Paper Submitted 31/Dec/2017; Revised 13/April/2018; Accepted 11/Jan/201

Polymorphisms in base excision repair genes and thyroid cancer risk

We wish to thank Luisa Manso Oliveira, Lylliane Luz, Silvia Morgado Amaro and Maria Catarina Soveral for technical support. This study was supported by the Center for Research in Human Molecular Genetics (CIGMH), Projects PTDC/SAU-OSM/105572/2008, PTDC/SAU-ESA/102367/2008 and PTDC/QUI/67522/2006 from Fundacao para a Ciencia e Tecnologia (FCT) and Fundacao Calouste Gulbenkian (Grant 76438/2006). The grants to M. Pingarilho (SFRH/BD/22612/2005) from FCT are also acknowledgedThyroid cancer (TC) is the most frequent endocrine malignancy, accounting however for only 1-2\% of all human cancers, and tilt: best-established risk factor for TC is radiation exposure, particularly during childhood. Since the BER pathway seems to play an important role in the repair of DNA damage induced by IR and other genotoxicants, we carried out a hospital-based case-control study in order to evaluate the potential modifying role of 6 BER polymorphisms on the individual susceptibility to non-familial TC in 109 TC patients receiving iodine-131, and 217 controls matched for age ( 2 years), gender and ethnicity. Our results do not reveal a significant involvement of XRCCI Arg194Trp and Arg399Gln, OGGI Ser326Cys, APEXI Asp148Glu, MUTYH Gln335His and,PARPI Val762Ala polymorphisms on the individual susceptibility towards TC, mostly in aggreement with the limited available evidence. By histological stratification analyis, we observed that the association between the presence of heterozygozity in the MUTYH Gln335His polymorphism and TC risk almost reached significance for the papillary subtype of TC. This was the first time that the putative association between this polymorphism and TC susceptibility was evaluated. However, since the sample size was modest, the possibility of a type I error should not be excluded and this result should, therefore, be interpreted with caution. More in depth studies involving larger populations should be pursued in order to further clarify the potential usefulness of the MUTYH Gln335His genotype as a predictive biomarker of susceptibility to TC and the role of the remaining BER polymorphisms on TC susceptibility.publishersversionpublishe

A new urban wind turbine blade design using a pressure-load inverse method

This paper presents the design methodology of a new wind turbine blade section that achieves high performance in urban environment by increasing the maximum lift. For this purpose, a turbomachine blade rows inverse design method was applied to obtain a new wind turbine blade section with constant pressure-load along the chord, at the design inlet angle. In comparison with conventional blade designs, the new blade section has increased maximum lift, reduced leading edge suction peak and controlled soft-stall behaviour,due to the strength reduction of the adverse pressure gradient on the blade suction surface.Wind tunnel experimental results confirmed the computational results

Influence of the iron content on the solidification behaviour of cast aluminium bronze used in marine applications

The effect of iron addition to Cu-Al-Ni alloys (in the zone of the chemical composition of commercial aluminium bronze) has been studied. The quaternary alloys were melted from a base Cu-Al-Ni alloy with iron additions up to ~6 at.%. Simultaneous Differential Thermal Analysis and Termogravimetry (DSC/TGA) and isothermal homogenisation with rapid cooling have been employed to determine the equilibrium phases at different temperatures and the existing invariant reactions. The alloys were observed by Optical Microscopy (OP) and by Scanning Electron Microscopy (SEM). The chemical analysis of the phases has been determined by Energy-Dispersive Spectroscopy (EDS). The results obtained allow the determination of the effect of the iron content in the sequence of phase formation. The chemical compositions of the phases obtained are compared with the same phases in the commercial alloys, with other alloying elements being present. The effect of iron content on the “liquidus” temperature and phase compositions of the invariant reactions detected, in the range of compositions studied, are presented