A new way of identifying FRBs

Thanks to the radio telescopes such as those at CHIME, which scan the entire northern sky every day, the number of detected FRBs has grown exponentially in recent years. The research team used a new set of statistical tools they developed to go over the data gathered by CHIME between September 30, 2019, and May 1, 2021, to confirm whether what they were saying were indeed FRBs.

“We combed through the data to find every repeating source detected so far, including the less obvious ones,” says Ziggy Pleunis, the first author of the paper who started working on the research as a PhD student at McGill University. He is now a Dunlap Postdoctoral Fellow at the Dunlap Institute for Astronomy and Astrophysics. “These new tools were essential for this study because we can now accurately calculate the probability that two or more bursts coming from similar locations are not just a coincidence. It should be very useful for similar research going forward.”

“These new discoveries will allow the scientific community to study more repeating FRBs in fantastic detail across the full electromagnetic spectrum and help answer a major open-question in the field: Do repeating and non-repeating FRBs originate from distinct populations?” Adds Aaron Pearlman, an FRQNT postdoctoral fellow at McGill University’s Trottier Space Institute who also collaborated on the paper. “I’m excited for the new insights that will be unlocked as a result of our study.”

“It is exciting that CHIME/FRB saw multiple flashes from the same locations, as this allows for the detailed investigation of their nature,” says Adaeze Ibik, a PhD student in the David A. Dunlap Department for Astronomy and Astrophysics at the University of Toronto, who has led the search for the galaxies in which some of the newly identified repeating FRBs are embedded.

“We were able to hone in on some of these repeating sources and have already identified likely associated galaxies for two of them.”

Shedding light on the mysterious origins of FRBs

FRBs are considered one of the biggest mysteries in astronomy, but their exact origins are unknown. Astronomers do know that they come from far outside our Milky Way and are most likely produced by the cinders left behind after stars die.

One unexpected finding described in the paper is that contrary to what has previously been thought, all FRBs may be repeaters rather than one-offs. It is simply that many repeating FRBs are surprisingly inactive, producing fewer than one burst per week, and that the apparently one-off FRBs have simply not been observed for long enough until now for a second burst to be detected.

Pleunis notes that this new research brings us closer to understanding what FRBs are.

“FRBs are likely produced by the leftovers from explosive stellar deaths. By studying repeating FRB sources in detail, we can study the environments that these explosions occur in and understand better the end stages of a star’s life. We can also learn more about the material that’s being expelled before and during the star’s demise, which is then returned to the galaxies that the FRBs live in.”

But new Edith Cowan University (ECU) research indicates this could also be a signal for another sinister health concern of ageing: late-life dementia.

To investigate the relationship between muscle function and dementia, the research teams from ECU’s Nutrition & Health Innovation Research Institute and Centre for Precision Health used data from the Perth Longitudinal Study of Ageing in Women to examine more than 1000 women with an average age of 75.

In collaboration with the University of Western Australia, the team measured the women’s grip strength and the time it took for them to rise from a chair, walk three metres, turn around and sit back down — known as a timed-up-and-go (TUG), test.

These tests were repeated after five years to monitor any loss of performance.

Over the next 15 years, almost 17 per cent of women involved in the study were found to have had a dementia event, categorised as a dementia-related hospitalisation or death.

The team found lower grip strength and slower TUG were significant risk factors for presenting with dementia, independent of genetic risk and lifestyle factors such as smoking, alcohol intake and physical activity levels.

Relationship established

The women with the weakest grip strength were found to be more than twice as likely to have a late-life dementia event than the strongest individuals.

A similar relationship emerged between TUG performance and dementia, with the slowest in their TUG test more than twice as likely to experience dementia than the quickest.

When researchers looked at the changes in grip strength and TUG test results after five years, a decrease in performance was also linked with greater dementia risk.

Those who had experienced the biggest decline in grip strength and TUG speed were approximately 2 and 2.5 times more likely, respectively, to have had a dementia event, compared to those in the group who recorded the smallest decline in performance.

Women with the biggest drop in TUG performance were found to be over four times more likely to have a dementia-related death than the fastest.

An early warning

Senior researcher Dr Marc Sim said grip strength, which can be easily measured using a handheld device known as a dynamometer, may be a measure of brain health due to the overlapping nature of cognitive and motor decline.

“Possibly due to a range of underlying similarities, grip strength may also present as a

surrogate measure of cardiovascular disease, inflammation and frailty, which are known risk factors for dementia,” Dr Sim said.

Dr Sim said the findings from the study could help health professionals to identify dementia risk in patients earlier.

“Both grip strength and TUG tests aren’t commonly performed in clinical practice, but both are inexpensive and simple screening tools,” he said.

“Incorporating muscle function tests as part of dementia screening could be useful to identify high-risk individuals, who might then benefit from primary prevention programs aimed at preventing the onset of the condition such as a healthy diet and a physically active lifestyle.

“The exciting findings were that decline in these measures was associated with substantially higher risk, suggesting that if we can halt this decline, we may be able to prevent late-life dementias. However, further research is needed in this area.”

Centre for Precision Health Director Professor Simon Laws said there has been encouraging progress in identifying early warning signs of dementia.

“We are now starting to see a number of simple yet indicative screening assessments that could be combined with other biological and clinical measures to provide a holistic risk-profile for individuals presenting to their GP with, for example, memory concerns,” he said.

‘Impaired muscle function, including its decline, is related to greater long-term late-life dementia risk in older women’ was published in the Journal of Cachexia, Sarcopenia and Muscle.

Cybersickness is a form of motion sickness that occurs from exposure to immersive VR and augmented reality applications.

A new study, led by researchers at the University of Waterloo, found that the subjective visual vertical — a measure of how individuals perceive the orientation of vertical lines — shifted considerably after participants played a high-intensity VR game.

“Our findings suggest that the severity of a person’s cybersickness is affected by how our senses adjust to the conflict between reality and virtual reality,” said Michael Barnett-Cowan, a professor in the Department of Kinesiology and Health Sciences. “This knowledge could be invaluable for developers and designers of VR experiences, enabling them to create more comfortable and enjoyable environments for users.”

The researchers collected data from 31 participants. They assessed their perceptions of the vertical before and after playing two VR games, one high-intensity and one low-intensity.

Those who experienced less sickness were more likely to have the largest change in the subjective visual vertical following exposure to VR, particularly at a high intensity. Conversely, those who had the highest levels of cybersickness were less likely to have changed how they perceived vertical lines. There were no significant differences between males and females, nor between participants with low and high gaming experience.

“While the subjective vertical visual task significantly predicted the severity of cybersickness symptoms, there is still much to be explained,” said co-author William Chung, a former Waterloo doctoral student who is now a postdoctoral fellow at the Toronto Rehabilitation Institute.

“By understanding the relationship between sensory reweighting and cybersickness susceptibility, we can potentially develop personalized cybersickness mitigation strategies and VR experiences that take into account individual differences in sensory processing and hopefully lower the occurrence of cybersickness.”

As VR continues to revolutionize gaming, education and social interaction, addressing the pervasive issue of cybersickness — marked by symptoms such as nausea, disorientation, eye strain and fatigue — is critical for ensuring a positive user experience.