Scientists

Children whose mothers took high doses of vitamin D (2,800 IU/day) during pregnancy have better verbal and visual memory at the age of 10—among other cognitive functions—than children whose mothers took a standard dose of this vitamin (400 IU/day). This is the conclusion of a study, published in JAMA Network Open, based on a reanalysis of data from 498 children in another study on childhood asthma in Denmark.

Last Saturday, the Director-General of the World Health Organisation (WHO), Tedros Adhanom Ghebreyesus, declared that the Ebola outbreak caused by the Bundibugyo virus in the Democratic Republic of the Congo and Uganda constitutes a public health emergency of international concern (PHEIC), following consultation with the organisation’s member states. By 15 May, 246 suspected cases and 80 deaths had been reported in three health zones: Rwampara, Mongbwalu and Bunia.

A team from the United States analyzed 611 samples from 341 model mouse strains stored at the Mutant Mouse Resource and Research Centers (MMRRC), a research resource network supported by the National Institutes of Health (NIH). By comparing the identity of each strain with its actual genetic profile, they found that approximately half of the samples showed discrepancies. Although the expected engineered mutation was generally present and many inconsistencies were relatively minor, some had the potential to compromise the validity and reproducibility of the experiments by introducing hidden genetic variables that could alter biological outcomes. The findings are published in Science.

The eyes are connected to the brain via the retina, which makes it a potential pathway for brain stimulation. A study published in Cell Reports Physical Science has used contact lenses equipped with a system for transcorneal electrical stimulation to treat depression in animal models of the disorder. Mice fitted with the device showed behavioural improvements, including increased sociability, as well as physiological changes, such as the restoration of altered neural connections. The results were comparable to those obtained with fluoxetine —known commercially as Prozac— administered for three weeks in one of the mouse groups.

An analysis by World Weather Attribution shows that players and fans face a much higher risk of extreme heat and humidity at the 2026 FIFA World Cup—to be held from June 11 to July 19 in North America—compared to the 1994 tournament held on the same continent. The report analyzes the likelihood that each of the 104 matches to be played in Canada, the United States, and Mexico will meet the safety guidelines set by the FIFPRO players’ union. Nearly a quarter of the matches will be played when conditions exceed a wet-bulb temperature of 26°C—an index that measures the body’s ability to cool itself—which requires cooling breaks. In addition, five matches will exceed the 28°C threshold for this indicator—equivalent to 38°C in dry heat—a limit set by FIFPRO for postponing matches.

A team has proposed an indicator known as the plastic particle footprint (PPF) to measure the environmental impact of microplastics and nanoplastics in products. In an article published in Science Advances, the authors apply this calculation to four everyday items and claim that calculating this footprint could “radically change the best material option”. For example, a polyester T-shirt and a cotton one have a similar carbon footprint, but the PPF of the former is higher than that of the cotton garment.

A research team presents a wireless polygraph – colloquially known as a “lie detector” – that attaches to the chest to diagnose stress in adults and sleep disorders in children. According to the study, published in Science Advances, the device is able to identify episodes of waking, hypopnoea and apnoea in children.

A global analysis of data from more than 232 million people shows that the rise in obesity has slowed or stabilised in some high-income countries since the 1990s among children and adolescents, and, a decade later, among adults. In Spain, this stabilisation or even a slight decline is also observed. In most low- and middle-income regions, the prevalence of obesity continues to increase and, in some cases, has already surpassed that of more developed economies. The study, published in Nature, included 4,050 studies covering the period from 1980 to 2024 across 200 countries.

A study conducted by the Barcelona Institute for Global Health (ISGlobal), in collaboration with the Barcelona Supercomputing Center (BSC-CNS), has analyzed short-term mortality associated with the combined effects of multiple air pollutants in 31 European countries. According to their estimates, this exposure is associated with 146,500 premature deaths per year and affects people differently depending on age, sex, and cause of death: young men are more vulnerable than young women, but the pattern reverses with age. The authors, who published the study in Nature Health, propose creating a new generation of impact-based early warning systems specifically targeting vulnerable groups.