Resumo A pandemia de COVID-19 tem desafiado pesquisadores e gestores a encontrar medidas de saúde pública que evitem o colapso dos sistemas de saúde e reduzam os óbitos. Esta revisão narrativa buscou sistematizar as evidências sobre o impacto das medidas de distanciamento social na epidemia de COVID-19 e discutir sua implementação no Brasil. Foram triados artigos sobre o efeito do distanciamento social na COVID-19 no PubMed, medRXiv e bioRvix, e analisados atos do poder público nos níveis federal e estadual para sumarizar as estratégias implementadas no Brasil. Os achados sugerem que o distanciamento social adotado por população é efetivo, especialmente quando combinado ao isolamento de casos e à quarentena dos contatos. Recomenda-se a implementação de medidas de distanciamento social e de políticas de proteção social para garantir a sustentabilidade dessas medidas. Para o controle da COVID-19 no Brasil, é imprescindível que essas medidas estejam aliadas ao fortalecimento do sistema de vigilância nos três níveis do SUS, que inclui a avaliação e uso de indicadores adicionais para monitorar a evolução da pandemia e o efeito das medidas de controle, a ampliação da capacidade de testagem, e divulgação ampla e transparente das notificações e de testagem desagregadas.

No abstract

The universal core of metabolism could have emerged from thermodynamically favoured prebiotic pathways at the origin of life. Starting with H 2 and CO 2 , the synthesis of amino acids and mixed fatty acids, which self-assemble into protocells, is favoured under warm anoxic conditions. Here, we address whether it is possible for protocells to evolve greater metabolic complexity, through positive feedbacks involving nucleotide catalysis. Using mathematical simulations to model metabolic heredity in protocells, based on branch points in protometabolic flux, we show that nucleotide catalysis can indeed promote protocell growth. This outcome only occurs when nucleotides directly catalyse CO 2 fixation. Strong nucleotide catalysis of other pathways (e.g. fatty acids and amino acids) generally unbalances metabolism and slows down protocell growth, and when there is competition between catalytic functions cell growth collapses. Autocatalysis of nucleotide synthesis can promote growth but only if nucleotides also catalyse CO 2 fixation; autocatalysis alone leads to the accumulation of nucleotides at the expense of CO 2 fixation and protocell growth rate. Our findings offer a new framework for the emergence of greater metabolic complexity, in which nucleotides catalyse broad-spectrum processes such as CO 2 fixation, hydrogenation and phosphorylation important to the emergence of genetic heredity at the origin of life.

The universal core of metabolism could have emerged from thermodynamically favoured prebiotic pathways at the origin of life. Starting with H2 and CO2, the synthesis of amino acids and mixed fatty acids, which self-assemble into protocells, is favoured under warm anoxic conditions. Here we address whether it is possible for protocells to evolve greater metabolic complexity, through positive feedbacks involving nucleotide catalysis. Using mathematical simulations to model metabolic heredity in protocells, based on branch points in proto-metabolic flux, we show that nucleotide catalysis can indeed promote protocell growth. This outcome only occurs when nucleotides directly catalyse CO2 fixation. Strong nucleotide catalysis of other pathways (e.g. fatty acids, amino acids) generally unbalances metabolism and slows down protocell growth, and when there is competition between catalytic functions cell growth collapses. Autocatalysis of nucleotide synthesis can promote growth but only if nucleotides also catalyse CO2 fixation; autocatalysis alone leads to the accumulation of nucleotides at the expense of CO2 fixation and protocell growth rate. Our findings offer a new framework for the emergence of greater metabolic complexity, in which nucleotides catalyse broad-spectrum processes such as CO2 fixation, hydrogenation and phosphorylation important to the emergence of genetic heredity at the origin of life.

Jair Bolsonaro was elected President of Brazil with 55 per cent of the vote on 28th October, defeating the Workers' Party candidate Fernando Haddad, and will take office on 1st January 2019. Bolsonaro and his political allies are already laying the groundwork for his ascension to power. It is clear that his election will have a devastating impact across society, with politics and policies which will target the most marginalised. He will also cement his own power base, which lies within the three right-wing blocs in National Congress of 'Beef, Bible and Bullet' -agribusiness, evangelical Christians and federal deputies aiming to ease legislation around firearms. Many of Bolsonaro's hateful comments have been widely reported -that he would rather have a dead son than an openly gay son, telling a woman she was too ugly to rape, and advocating torture -and he has been referred to as the 'Trump of the Tropics'.