Physical activity is associated with significant reductions in depressive symptoms in children and adolescents, according to a systematic review and meta-analysis published in JAMA Pediatrics that included 21 studies with 2,400 participants. The largest decreases in these symptoms were found in those aged 13 years and older.

Constant checking of social media activity in early adolescence is associated with changes in the brain's sensitivity to rewards and punishments. This is the conclusion of a study involving 169 12- and 13-year-old students in the United States with Facebook, Instagram and Snapchat profiles, according to JAMA Pediatrics.

An international study led by Spanish researchers has succeeded in reconstructing the ancestors of the CRISPR-Cas system present in extinct bacteria from up to 2.6 billion years ago. The reconstructed systems work and are more flexible than the current ones. According to the authors, this could open up new avenues for gene editing. The results are published in the journal Nature Microbiology.

The Minister of Health, Carolina Darias, announced today at a press conference that in view of the increase in cases of covid-19 in China following the end of the covid zero policy, Spanish airports are going to require passengers arriving from that country to take a negative test for covid-19 or a complete vaccination schedule. The first flight affected by health control measures will arrive at Adolfo Suárez Madrid-Barajas Airport at 18:00 on 31 December.

The end of the zero covid policy in China is leading to an increase in the number of cases and has revived the question of whether the epidemiological situation in China could favour the emergence of new variants of the SARS-CoV-2 coronavirus.

Artificial intelligence algorithms using ChatGPT - the OpenAI company's GPT-3 language model - can identify speech features to predict the early stages of Alzheimer's disease with 80 per cent accuracy. The neurodegenerative disease causes a loss of the ability to express oneself that the algorithms could recognise, according to the journal PLOS Digital Health.

Air pollution has been repeatedly linked to the risk of developing dementia. In addition to confirming this association, a study published in the journal PNAS has analysed the individual risk posed by the components present in PM2.5 fine particulate matter.

The establishment of the baby's microbiota occurs around the time of birth, when it receives bacteria directly from the mother. A study in the journal Cell suggests that genes can also be transmitted between them by horizontal transfer, without the need for the passage of these micro-organisms.

The Court of Justice of the European Union has condemned Spain for failing to take the necessary measures to prevent continued non-compliance with air pollution limits in Madrid and the metropolitan area of Barcelona between 2010 and 2018. It also includes Baix Llobregat between 2010 and 2017.

Bubble boy syndrome is a very serious condition caused by combined immunodeficiency. It is sometimes caused by certain mutations in the gene that codes for the Artemis protein. A phase I-II clinical trial has tested a gene therapy that adds a correct copy of the gene. The results are published in the journal NEJM.