Infection with the bacterium Helicobacter pylori is a known risk factor for stomach cancer. Its link to colorectal cancer, however, remains an unconfirmed hypothesis. An international team has reviewed 43 studies on this subject and found that 22 per cent of colorectal cancer cases could potentially be linked to this infection, although when they selected the 14 most reliable studies, the figure fell to 12 per cent. According to the authors, exposure to Helicobacter pylori could be contributing significantly to the number of cases of colon cancer worldwide, but they point out that their study is only exploratory and that more robust research, such as clinical trials, is needed to establish a causal link. The results have been published in eGastroenterology.

A study has analysed structural changes in the female brain during the three main hormonal transitions: puberty, pregnancy and the menopause. To do this, using longitudinal neuroimaging – which records images of the brain over time – the researchers compared women transitioning from one hormonal phase to another with participants currently in those hormonal phases – more than 1,000 women in total. The results, published in Nature Communications, show that the transitions of puberty and pregnancy lead to a reduction in cortical grey matter, whilst women going through the menopause did not show a significant decrease in either cortical grey matter or total brain volume.

Various studies have shown that smokers have a lower risk of developing Parkinson’s disease, but the causes remain unknown. A study has analysed the role played by carbon monoxide — a toxic gas produced by the combustion of tobacco — in this association. To this end, the team conducted a twelve-year follow-up study of more than half a million adults in China. The results show that regular smoking was associated with an increased risk of lung cancer, ischaemic heart disease, stroke and all-cause mortality, but with a lower risk of Parkinson’s disease. Most strikingly, amongst people who had never smoked, higher levels of exhaled carbon monoxide—which the authors measured—were associated with a lower risk of Parkinson’s disease. According to the study, published in JAMA Neurology, these findings demonstrate a possible protective role of carbon monoxide in the disease, rather than smoking itself.

Following the publication of the results of the PISA 2025 report, the question arises as to how to interpret them and explain the possible causes of the decline in reading and maths results, both internationally and in Spain. We have sought the views of experts in education, sociology, inequality, educational technology and pedagogy.

The artificial intelligence (AI) company OpenAI has unveiled GPT-6 Astra, “the world’s smartest and best-aligned model”, according to the company. The new model will use a technique known as ‘opaque recurrence’, which allows it to operate outside the sequential thinking of most reasoning models and which is causing concern amongst AI safety experts due to the possibility that the model’s thought process may be more difficult to monitor.

The peaks of European mountains such as the Pyrenees or the Sierra Nevada may be gaining plant species as the climate warms, but this apparent increase in biodiversity is masking a growing wave of local extinctions. These are the main conclusions of a study published in the journal Science, which includes Spanish participation and analyses nearly a thousand vegetation plots spread across 62 European mountain peaks. The reason is that higher-altitude mountain regions have gained plant species in recent decades as plants from lower altitudes have expanded up the slopes, but this may mask the decline or disappearance of specialised, high-altitude resident species.

Chemotherapy-induced peripheral neuropathy is a side effect of platinum-based cancer treatments that affects more than 60 per cent of patients and causes pain, a burning sensation and numbness. The psychedelic compound psilocybin could help prevent it, according to researchers behind a study using mouse models published in Science. Two doses of psilocybin administered prior to treatment prevented peripheral neuropathy for up to six cycles of chemotherapy without reducing its anti-tumour effects. The author of another perspective article on this study, also in Science, states that “the challenge now is to translate this understanding of the underlying mechanisms into carefully designed clinical trials”.

Thanks to the Voyager probe, we know that Saturn has a long-lasting hexagonal wave at its north pole, which is linked to a powerful jet of matter and energy. Now, a team led by the University of the Basque Country has discovered, for the first time, the presence of a decagonal wave at the south pole. The observations, carried out from the ground and using the Hubble Space Telescope, show that the decagon appears to have formed between 2023 and 2025 and may continue to evolve, in contrast to the more than 40 years of stability exhibited by the hexagon. The research is published in Science Advances and suggests that the ten-sided shape could be a meandering wave trapped by the curvature of a dominant atmospheric current.

A team of researchers, including Nobel Laureate in Physics Roger Penrose, has observed for the first time an effect of gravity on a falling quantum object that had long been predicted. The result demonstrates that a fundamental principle underpinning Einstein’s theory of gravity remains consistent with the behaviour of matter in the quantum world. The study, published in the journal Science Advances, does not unify quantum mechanics and gravity, nor does it prove that gravity itself is quantum.

A meta-analysis involving over a million participants has identified more than a thousand genetic variants associated with human personality. The study, published today in the journal Nature, examines the possible links between DNA variations and differences in personality. The results do not suggest that personality can be predicted from DNA, but rather that some variants may influence behavioural traits, whilst acknowledging that other environmental factors may have a greater impact. In their work, the authors focus on five traits: extraversion, agreeableness, conscientiousness, neuroticism and openness to experience.