Browsing by Issue Date, starting with "2007-08"
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- Adaptive mutations in bacteria: high rate and small effectsPublication . Perfeito, Lília; Fernandes, Lisete; Mota, Catarina; Gordo, IsabelEvolution by natural selection is driven by the continuous generation of adaptive mutations. We measured the genomic mutation rate that generates beneficial mutations and their effects on fitness in Escherichia coli under conditions in which the effect of competition between lineages carrying different beneficial mutations is minimized. We found a rate on the order of 10–5 per genome per generation, which is 1000 times as high as previous estimates, and a mean selective advantage of 1%. Such a high rate of adaptive evolution has implications for the evolution of antibiotic resistance and pathogenicity.
- Portugal making a difference with children and families: the GADIF modelPublication . Fuertes, MarinaPortugal is a culture grounded in strong traditions and family. Yet, social changes like women returning to the workforce and a decreas ed national birth rate are impacting the traditional family structure and care giving environments of children. Female employment has been increasing steadily in P ortugal over the last three decades (Galego & Pereira, 2006) and the total fert ility rate decreasing from 4.1 to 2.8 (INE, 2006). Furthermore, extended family me mbers, like grandparents, no longer reside close by to their children and grandc hildren as in the past, because of a changing labor market. Many of the younger gen eration are leaving their rural communities to flock to urban areas because o f job opportunities, leaving behind older relatives who would have otherwise par ticipated in the daily care of children. Given these social and economic changes, children are spending more time in out-of-home care with non-familial caregive rs. Yet, government regulations and guidelines in early care and educat ion (ECCE) and early intervention (EI) are only just emerging; it contin ues to be a work in progress.
- Influence of processing conditions on the morphological and mechanical properties of compatibilized PP/LCP blendsPublication . Filipe, Susana; Maia, João Manuel; Leal, Catarina R.; Cidade, Maria TeresaThe main aim of this work is to study theinfluence of the application of different processing conditionson the morphological and mechanical properties of thermo-plastic/LCP blends, in which the viscosity ratios are inferiorto unity and decrease with increasing temperature. The waythe microstructure evolves along the extruder determines thefinal morphology and thus, the mechanical performance ofthe systems. In the present case, the mechanical properties arerelated with the degree of fibrillation in the final composites.The best degree of fibrillation was obtained for low screwspeeds and temperatures and for intermediate outputs. Theuse of high screw speeds and processing temperatures resultsin a decrease of the viscosity ratio, in the former case via anincrease in the viscous dissipation, at the regions of highershear rates (kneading-elements). The application of a lowerprocessing temperature is advantageous for deformation,break-up, and fibrillar formation because of the higher viscos-ity ratios and higher shear stresses involved.
- Cancer incidence projections for Lisbon and Santarém districts: an aid to radiotherapy services planningPublication . Monsanto, Fátima; Carolino, Elisabete; Ramos, R.; Sá, Ana Cravo; Coelho, Carina MarquesWill the existing means in Radiotherapy respond to the needs of the potential user population in 2014 for Lisbon and Santarém districts? Number of treatment units? Number of Radiotherapy Technologists? Temporal variations of the dimension and age structure of the populations: Coastal areas/Interior areas, Urban areas/Rural areas. Temporal variations in the incidence of several types of cancer. Overall objectives: evaluate of the necessities of Radiotherapy for Lisbon and Santarém districts in 2014 and elaboration of proposals that aim the access/use for the potential user population.