Summer conjures up images of swimming pools, beaches, holidays and also, buzzing and bites. Mosquitoes have been with us all our lives, but globalisation has led to the arrival in Spain of invasive species capable of causing diseases such as dengue and yellow fever. How can we distinguish dangerous species and avoid their bites?

Two studies published in the journal Nature use artificial intelligence (AI) to try to predict the weather. One system, trained on nearly 40 years of global weather data, is capable of predicting global weather patterns up to a week in advance. The second, called NowcastNet, combines physics rules and deep learning for immediate prediction of precipitation, including extreme precipitation.

The World Meteorological Organisation (WMO) has declared the onset of El Niño conditions on Tuesday. "The declaration of El Niño by the WMO is the signal for governments around the world to mobilise preparations to limit the impacts on our health, our ecosystems and our economies," said WMO Secretary-General Petteri Taalas. According to the WMO statement, El Niño conditions have developed in the tropical Pacific for the first time in seven years, setting the stage for a likely rise in global temperatures and altered weather and climate patterns.

Parkinson's disease is usually diagnosed when there is already extensive neuronal damage and symptoms are evident. Now, researchers at Cardiff University in the UK have used movement and sleep quality data from wearable accelerometers and concluded that they can help identify the disease early, years before clinical diagnosis. Although there is no effective preventive treatment, the authors propose that the tool can determine people at risk of developing Parkinson's disease and identify participants for clinical trials of neuroprotective treatments. The results are published in the journal Nature Medicine.

Klotho is a protein whose concentrations tend to decline with age and which has been linked to ageing processes. Now, researchers have found that administration of the protein improves cognitive function in aged rhesus macaques, including benefits in spatial and working memory. According to the authors, who publish the results in the journal Nature Aging, its use "may be therapeutic in humans".

The IceCube neutrino observatory, built deep under Antarctic ice, has detected the emission of high-energy neutrinos from within the Milky Way. According to the research, published in the journal Science, this is the first time scientists have obtained solid evidence for the emission of these particles within our galaxy, as they had previously identified high-energy neutrino emission from extragalactic sources.

The International Pulsar Timing Array (IPTA) consortium has discovered evidence for the existence of a cosmic background of gravitational waves. The results, published by different IPTA consortia in several scientific journals, would show that this cosmic background would be the result of collisions of supermassive black holes. In 2015, researchers from the LIGO and Virgo collaborations made the first direct observation of gravitational waves caused by the collision of two stellar-mass black holes. These waves oscillate several times per second. What the consortia have now found are gravitational waves emitted by supermassive binary black holes at the centre of galaxies, waves that oscillate on timescales of many years.

Reuters has reported that aspartame, one of the most common artificial sweeteners, will be listed as "possibly carcinogenic to humans" by the International Agency for Research on Cancer (IARC), an agency of the World Health Organisation, in July.

The use of hormonal replacement therapy (HRT) for menopause is associated with the development of dementia and Alzheimer's disease, even for short prescriptions before the age of 55, according to an analysis of data from the Danish national registry published in The BMJ. The research - which observes associations and cannot determine causality - also shows that the use of progesterone alone and vaginal oestrogen are not associated with the development of dementia.

Pre-exposure prophylaxis (PrEP), which usually consists of taking a daily oral anti-HIV drug, is a highly effective measure to prevent HIV infection. However, it only works well if people strictly follow the protocol, and some people end up not adhering to it. To improve this situation, researchers have tested an implant under the skin of non-human primates that releases the antiretroviral drug islatravir and maintains adequate concentrations for at least 20 months. The results, published in the journal Science Translational Medicine, show complete protection against infection with repeated exposure.