Perplexidades e incertezas da regulação dos media na Europa

A regulação dos media tem ganho relevo nas agendas nacionais e internacionais mas nem sempre a utilização corrente do conceito é consistente, correndo o risco de significar tudo e nada em simultâneo. Independentemente do intenso e profícuo debate concetual que o tema suscita na comunidade académica, julgamos pertinente o estudo das estruturas de regulação mediática que operam no terreno da União Europeia. Este trabalho reflete sobre as entidades de regulação mediática que atuam na defesa do interesse público, ainda que existam as mais diversas modalidades de enunciação e de defesa desse interesse pelos vários estados, e decorre de um esforço de investigação coletivo, enquadrado no projeto “Regulação dos Media em Portugal: O Caso da ERC”, que agregou elementos sobre os organismos reguladores dos media na Europa.

Fine time scaling of purifying selection on human nonsynonymous mtDNA mutations based on the worldwide population tree and mother-child pairs

A high-resolution mtDNA phylogenetic tree allowed us to look backward in time to investigate purifying selection. Purifying selection was very strong in the last 2,500 years, continuously eliminating pathogenic mutations back until the end of the Younger Dryas (∼11,000 years ago), when a large population expansion likely relaxed selection pressure. This was preceded by a phase of stable selection until another relaxation occurred in the out-of-Africa migration. Demography and selection are closely related: expansions led to relaxation of selection and higher pathogenicity mutations significantly decreased the growth of descendants. The only detectible positive selection was the recurrence of highly pathogenic nonsynonymous mutations (m.3394T>C-m.3397A>G-m.3398T>C) at interior branches of the tree, preventing the formation of a dinucleotide STR (TATATA) in the MT-ND1 gene. At the most recent time scale in 124 mother-children transmissions, purifying selection was detectable through the loss of mtDNA variants with high predicted pathogenicity. A few haplogroup-defining sites were also heteroplasmic, agreeing with a significant propensity in 349 positions in the phylogenetic tree to revert back to the ancestral variant. This nonrandom mutation property explains the observation of heteroplasmic mutations at some haplogroup-defining sites in sequencing datasets, which may not indicate poor quality as has been claimed.