Mobile phone use may affect semen quality

A team from UNIGE and Swiss TPH has published a large study covering more than a decade of data on the effects of mobile phones on semen quality of young men

Peer-Reviewed Publication

UNIVERSITÉ DE GENÈVE

 

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SAMPLE OF HUMAN SPERMATOZOA.

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CREDIT: © RITA RAHBAN

Does electromagnetic radiation emitted by mobile phones affect semen quality? While various environmental and lifestyle factors have been proposed to explain the decline in semen quality observed over the last fifty years, the role of mobile phones has yet to be demonstrated. A team from the University of Geneva (UNIGE), in collaboration with the Swiss Tropical and Public Health Institute (Swiss TPH), has published a major cross-sectional study on the subject. It shows that frequent use of mobile phones is associated with a lower sperm concentration and total sperm count. However, researchers did not find any association between mobile phone use and low sperm motility and morphology. Read the results in Fertility & Sterility.

Semen quality is determined by the assessment of parameters such as sperm concentration, total sperm count, sperm motility and sperm morphology. According to the values established by the World Health Organization (WHO), a man will most probably take more than one year to conceive a child if his sperm concentration is below 15 million per milliliter. In addition, the percentage chance of pregnancy will decrease if the sperm concentration is below 40 million per milliliter.

Many studies have shown that semen quality has decreased over the last fifty years. Sperm count is reported to have dropped from an average of 99 million sperm per millilitre to 47 million per millilitre. This phenomenon is thought to be the result of a combination of environmental factors (endocrine disruptors, pesticides, radiation) and lifestyle habits (diet, alcohol, stress, smoking).

Assessing the impact of mobile phones

Is the mobile phone also to blame? After conducting the first national study (2019) on the semen quality of young men in Switzerland, a team from the University of Geneva (UNIGE) has published the largest cross-sectional study on this topic. It is based on data from 2886 Swiss men aged 18 to 22, recruited between 2005 and 2018 at six military conscription centres.

In collaboration with the Swiss Tropical and Public Health Institute (Swiss TPH), scientists studied the association between semen parameters of 2886 men and their use of mobile phones. ‘‘Men completed a detailed questionnaire related to their lifestyle habits, their general health status and more specifically the frequency at which they used their phones, as well as where they placed it when  not in use,’’ explains Serge Nef, full professor in the Department of Genetic Medicine and Development at the UNIGE Faculty of Medicine and at the SCAHT – Swiss Centre for Applied Human Toxicology, who co-directed the study.

These data revealed an association between frequent use and lower sperm concentration. The median sperm concentration was significantly higher in the group of men who did not use their phone more than once a week (56.5 million/mL) compared with men who used their phone more than 20 times a day (44.5 million/mL). This difference corresponds to a 21% decrease in sperm concentration for frequent users (>20 times/day) compared to rare users (<1 time>

Is 4G less harmful than 2G? 

This inverse association was found to be more pronounced in the first study period (2005-2007) and gradually decreased with time (2008-2011 and 2012-2018). ‘‘This trend corresponds to the transition from 2G to 3G, and then from 3G to 4G, that has led to a reduction in the transmitting power of phones,’’ explains Martin RÖÖsli, associate professor at Swiss TPH.

‘‘Previous studies evaluating the relationship between the use of mobile phones and semen quality were performed on a relatively small number of individuals, rarely considering lifestyle information, and have been subject to selection bias, as they were recruited in fertility clinics. This has led to inconclusive results,’’ explains Rita Rahban, senior researcher and teaching assistant in the Department of Genetic Medicine and Development in the Faculty of Medicine at the UNIGE and at the SCAHT, first author and co-leader of the study.

It doesn’t matter where you put your phone

Data analysis also seems to show that the position of the phone - for example, in a trouser pocket - was not associated with lower semen parameters. ‘‘However, the number of people in this cohort indicating that they did not carry their phone close to their body was too small to draw a really robust conclusion on this specific point,’’ adds Rita Rahban.

This study, like most epidemiologic studies investigating the effects of mobile phone use on semen quality, relied on self-reported data, which is a limitation. By doing so, the frequency of use reported by the individual was assumed to be an accurate estimate of exposure to electromagnetic radiation. To address this limitation, a study funded by the Federal Office for the Environment (FOEN) was launched in 2023. Its aim is to directly and accurately measure exposure to electromagnetic waves, as well as the types of use - calls, web navigation, sending messages - and to assess their impact on male reproductive health and fertility potential. The data will be collected using an application that each future participant will download to their mobile phone. The research team is actively recruiting participants for this study.

The aim is also to better describe the mechanism of action behind these observations. ‘‘Do the microwaves emitted by mobile phones have a direct or indirect effect? Do they cause a significant increase in temperature in the testes? Do they affect the hormonal regulation of sperm production? This all remains to be discovered,’’ concludes Rita Rahban.

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JOURNAL

Fertility and Sterility

DOI

10.1016/j.fertnstert.2023.09.009 

METHOD OF RESEARCH

News article

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Association between self-reported mobile phone use and the semen quality of young men

ARTICLE PUBLICATION DATE

1-Nov-2023

 

Smells like learning

Peer-Reviewed Publication

COLD SPRING HARBOR LABORATORY

 

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CSHL ASSOCIATE PROFESSOR SAKET NAVLAKHA TEAMED WITH SALK INSTITUTE RESEARCHER SHYAM SRINIVASAN AND OTHER INVESTIGATORS TO STUDY THE NEURONS RESPONSIBLE FOR SMELL DISCRIMINATION IN FRUIT FLIES AND MICE. ABOVE: A MOUSE BRAIN IMAGED BY SIMON DASTE AND ALEXANDER FLEISCHMANN AT BROWN UNIVERSITY. NEURONS THAT RESPOND TO AN ODOR ARE BRIGHTLY LIT.

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CREDIT: NAVLAKHA LAB/COLD SPRING HARBOR LABORATORY

Order wine at a fancy restaurant, and the sommelier might describe its aroma as having notes of citrus, tropical fruit, or flowers. Yet, when you take a whiff, it might just smell like … wine. How can wine connoisseurs pick out such similar scents?

Cold Spring Harbor Laboratory (CSHL) Associate Professor Saket Navlakha and Salk Institute researcher Shyam Srinivasan may have the answer. They have found that certain neurons allow fruit flies and mice to tell apart distinct smells. The team also observed that with experience, another group of neurons helps the animals distinguish between very similar odors.

The study was inspired by research from former CSHL Assistant Professor Glenn Turner. Years ago, Turner noticed something odd. When exposed to the same scent, some fruit fly neurons fired consistently while others varied from trial to trial. At the time, many researchers dismissed these differences as a product of background noise. But Navlakha and Srinivasan wondered whether the variations might serve a purpose. 

“There were two things we were interested in,” Navlakha says. “Where is this variability coming from? And is it good for anything?”

To address these questions, the team created a fruit fly smell model. The model showed that the variability came from a deeper circuit of the brain than previously thought. This suggested the variation was indeed meaningful.

Next, the team observed that some neurons respond differently to two very dissimilar odors, but the same to similar smells. The researchers called these neurons reliable cells. This small group of cells helps flies quickly distinguish between differing odors. Another much larger group of neurons responds unpredictably when exposed to similar smells. These neurons, which the researchers call unreliable cells, might help us learn to identify specific scents in a glass of wine, for example.

“The model we developed shows these unreliable cells are useful,” Srinivasan says. “But it requires many learning bouts to take advantage of them.”

Of course, this research isn’t just for wine drinkers. Srinivasan says the results might help explain how we learn to differentiate between similarities detected by other senses, and how we make decisions based on those sensory inputs. The findings could also lead to better machine-learning models. Unlike fruit fly and mouse neurons, computers generally respond the same to the same inputs.

“Maybe you don’t want a machine-learning model to represent the same input the same way every time,” Navlakha explains. “In more continual learning systems, variability could be useful.”

That means this research could someday help make AI more discerning and reliable.

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JOURNAL

PLoS Biology

DOI

10.1371/journal.pbio.3002206 

ARTICLE TITLE

Effects of stochastic coding on olfactory discrimination in flies and mice

 

Cigarette style warning labels could reduce people’s meat consumption

 Wednesday 1 November 2023

Peer-Reviewed Publication

DURHAM UNIVERSITY

Cigarette style graphic warning labels could reduce people’s meat consumption, according to new research published today (1 November).

The study suggests the use of warning labels on meat options could improve public health and reduce the UK’s carbon footprint.

The team from Durham University tested a range of warning labels including those which warn people of the damage to climate, health, and risk of pandemics. They found that all labels were effective at discouraging people from choosing meals with meat.

All warning labels, which showed a graphic image alongside text, reduced meat meal selections by seven to 10 percent. However, participants were most in favour of the climate warning labels which they also found the most credible.

The study is published in the academic journal, Appetite.

According to a recent YouGov poll, 72 per cent of the UK population classify themselves as meat eaters. The independent Climate Change Committee, which advises the UK government, recommends a 20 per cent reduction in meat and dairy consumption by 2030.

Jack Hughes carried out the research with his supervisors as part of his PhD research at the Department of Psychology at Durham University. He said: “Reaching net zero is a priority for the nation and the planet. As warning labels have already been shown to reduce smoking as well as drinking of sugary drinks and alcohol, using a warning label on meat-containing products could help us achieve this if introduced as national policy.”

A representative sample of 1,001 meat-eating adults were split into four groups which were shown pictures of hot meals you might buy in a canteen which contained either a health warning label, climate warning label, pandemic warning label, or no label.

They were asked to make 20 separate decisions on different meal choices and the team also asked how anxiety provoking and believable they found the labels. Future intentions to buy and eat the meal options, as well as how appealing the meals appeared, was measured. Participants also indicated how supportive they would be of the different labels if they were implemented as policy.

An example set of meals could be a meat pasta bake, fish pasta bake, vegetarian pasta bake and a vegan pasta bake.

Senior author on the paper, Dr Milica Vasiljevic from Durham University’s Department of Psychology said: “We already know that eating a lot of meat, especially red and processed meat, is bad for your health and that it contributes to deaths from pollution and climate change. Adding warning labels to meat products could be one way to reduce these risks to health and the environment.”

Ends

MEDIA INFORMATION

Interviews

Jack Hughes, PhD student in the Department of Psychology at Durham University, is available for interviews.

For requests, please contact Durham University’s Marketing and Communications Office on communications.team@durham.ac.uk or +44(0)191 334 8623. 

Images

There are three versions of the climate warning label image available to download from Dropbox:

• The climate warning label showing an image of a deforested area with factory smoke in the distance and the warning text - WARNING: Eating meat contributes to climate change (UN Food and Agricultural Organisation, 2020).
• The climate warning label on a small flag sticking in a burger.
• The climate warning label alongside a picture of a burger.

All images are similar to those used in the study.

Research paper

Impact of pictorial warning labels on meat meal selection: A randomised experimental study with UK meat consumers, by Jack Hughes, Mario Weick, and Milica Vasiljevic, Durham University. Published in Appetite, 1 November 2023.

A copy of the embargoed paper is available on request from communications.team@durham.ac.uk

About Durham University

Durham University is a globally outstanding centre of teaching and research based in historic Durham City in the UK.

We are a collegiate university committed to inspiring our people to do outstanding things at Durham and in the world.

We conduct research that improves lives globally and we are ranked as a world top 100 university with an international reputation in research and education (QS World University Rankings 2024).

We are a member of the Russell Group of leading research-intensive UK universities and we are consistently ranked as a top 10 university in national league tables (Times and Sunday Times Good University Guide, Guardian University Guide and The Complete University Guide).

For more information about Durham University visit: www.durham.ac.uk/about/

END OF MEDIA RELEASE – issued by Durham University Communications Office.

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JOURNAL

Appetite

Does your neighborhood affect your care after a stroke?

Peer-Reviewed Publication

AMERICAN ACADEMY OF NEUROLOGY

 NOVEMBER 1, 2023

MINNEAPOLIS – People who live in neighborhoods with lower socioeconomic status are less likely to receive clot-busting medications or undergo clot-removing procedures after they have a stroke than people who live in neighborhoods with higher socioeconomic status, according to a study published in the November 1, 2023, online issue of Neurology®, the medical journal of the American Academy of Neurology.

“These treatments can greatly reduce death and disability from stroke, but previous studies have shown that few people actually receive the treatments,” said study author Amy Ying Xin Yu, MD, of the University of Toronto in Canada. “We wanted to see how socioeconomic disparities play a role, especially in an area where everyone has access to universal health care.”

The study looked at all people living in Ontario, Canada, who had an ischemic stroke during a five-year period, for a total of 57,704 people. Ischemic stroke is caused by a blockage of blood flow to the brain and is the most common type of stroke.

The study looked to see how many of those people were treated with clot-busting drugs or surgery to remove blood clots.

Researchers also looked at participants’ neighborhoods and divided them into five groups based on their neighborhoods’ socioeconomic status, which was determined by factors such as the percentage of adults without a high school diploma, unemployment rate and income level.

A total of 17% of those living in the neighborhoods with the lowest socioeconomic status were treated, compared to 20% of those living in the neighborhoods with the highest socioeconomic status.

When researchers took into account other factors that could affect treatment, such as age, high blood pressure and diabetes, they found that people in the neighborhoods with the lowest socioeconomic status were 24% less likely to be treated than people in the neighborhoods with the highest socioeconomic status. There was no difference in treatment between the neighborhood with the lowest status and the middle three neighborhoods.

“Our study underscores the need for tailored interventions to address socioeconomic disparities in access to acute stroke treatments, including educational and outreach programs to increase awareness about the signs and symptoms of stroke in various languages and efforts to distribute resources more equitably across neighborhoods,” Yu said. “Further research is needed to examine the specific causes of these disparities, so we can find ways to address the larger systemic issues that need to be improved to better serve people from under-resourced neighborhoods.”

A limitation of the study was that researchers did not have information on other factors that could affect stroke treatment, such as the time symptoms started or how severe the stroke was.

The study was supported by ICES, a health research institute in Ontario; the Heart and Stroke Foundation of Canada; PSI Foundation; and Ontario Health Data Platform.

Learn more about stroke at BrainandLife.org, home of the American Academy of Neurology’s free patient and caregiver magazine focused on the intersection of neurologic disease and brain health. Follow Brain & Life® on Facebook, Twitter and Instagram.

When posting to social media channels about this research, we encourage you to use the hashtags #Neurology and #AANscience.

The American Academy of Neurology is the world’s largest association of neurologists and neuroscience professionals, with over 40,000 members. The AAN is dedicated to promoting the highest quality patient-centered neurologic care. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as Alzheimer’s disease, stroke, migraine, multiple sclerosis, concussion, Parkinson’s disease and epilepsy.

For more information about the American Academy of Neurology, visit AAN.com or find us on Facebook, Twitter, Instagram, LinkedIn and YouTube.

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JOURNAL

Neurology

Having a bad boss makes you a worse employee

Research underscores the hidden cost of abusive leadership, revealing that employees who prioritize career advancement suffer more than employees who prioritize job security

Peer-Reviewed Publication

STEVENS INSTITUTE OF TECHNOLOGY

If your boss stomps and yells, criticizes you, and then proceeds to take the credit for your work – even it is an isolated incident – it can take a profound toll on employee well-being and performance. But despite the many years of research, the precise mechanisms through which bad leadership impacts employees’ performance remain a subject of interest.

In a new study, first published online Oct. 30 in Group & Organization Management, an international group of researchers, led by Stevens Institute of Technology and University of Illinois Chicago, offer a novel explanation of the cognitive factors through which abusive leadership degrades employee performance — and helps explain why some employees are more vulnerable than others to the negative impact of abusive bosses.

“Thankfully, abusive supervision isn’t too common, but when it happens it leaves employees far less likely to take the initiative and work to improve business practices,” said Howie Xu, an author of the study and an assistant professor of management at Stevens. “We wanted to understand the cognitive factors behind that effect — and ask how companies can shield their employees from the negative impact of bad bosses.” 

Xu’s team surveyed employees and supervisors from 42 different South Korean companies, along with hundreds of US students, to explore the ways in which abusive supervision impacts “taking-charge” behavior by employees. Subjects were then ranked according to whether they actively seek positive opportunities for promotion and advancement or take a more preventative approach that prioritizes safety and job security.

“We theorized that both the drive to obtain rewards (promotion, bonuses) and the drive to avoid punishments (maintain job security) would shape the way employees respond to abusive bosses,” Xu explained. 

But that’s not what Xu and his team found. Rather, they found that employees who prioritize career advancement are strongly affected by abusive leadership while employees who prioritized job security remained just as likely to take charge after experiencing abusive supervision. Employees who prioritize advancement tend to hunker down and reduce taking-charge behavior after experiencing abusive supervision.”

“That’s a very surprising finding,” Xu said. “We found clear evidence that the signal from abusive leadership is much more salient to employees who care about advancement than it is to employees who care about security.”

One possible explanation, Xu explained, is that ambitious employees may perceive an abusive boss as having direct control over whether they will receive bonuses or opportunities for promotion. By contrast, bad bosses may be seen as having less direct control over firing decisions, which often require ratification by HR teams or more senior managers. 

That’s an important finding, because it suggests that organizations seeking to mitigate the impact of bad leadership should focus on empowering employees and making them feel valued and appreciated, rather than simply reassuring them their jobs are safe. “If a leader slips into abusive behavior, our research suggests that they should not only apologize, but also work to reassure employees of their value to the organization,” Xu said.

Unexpectedly, the variation in employee response to abusive supervision was broadly constant across both the Korean and US populations. “We think of these countries as culturally distinct, but there was no real difference in how employees responded to abusive bosses,” Xu said. “That might reflect the effect of globalization — or might be a sign that this is a universal trait that exists across many different cultures.” 

Researchers from Texas Tech University, Hunan University and Seoul National University also contributed to the paper.

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JOURNAL

Group & Organization Management

DOI

10.1177/10596011231204387 

METHOD OF RESEARCH

Survey

SUBJECT OF RESEARCH

People

ARTICLE TITLE

What Does Leaders’ Abuse Mean to Me? Psychological Empowerment as the Key Mechanism Explaining the Relationship Between Abusive Supervision and Taking Charge

ARTICLE PUBLICATION DATE

30-Oct-2023

 

How robots can help find the solar energy of the future

Finding the best material to make solar cells is a colossal task, but a research team at Osaka University has been using robotic systems and AI to make the search faster and more efficient

Peer-Reviewed Publication

OSAKA UNIVERSITY

 

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PICTURE OF AN OPERATING ROBOT PERFORMING A MICROWAVE CONDUCTIVITY MEASUREMENT.

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CREDIT: AKINORI SAEKI

Osaka, Japan – Solar energy is one of the most promising ways to power the world of the future. However, creating more efficient solar cells requires finding new and better materials. Now, in a study recently published in JACS Au, researchers at Osaka University have unveiled a solution: a system that automates key experimental and analytical processes to speed up research on solar materials considerably.

There’s more to solar cells than just silicon, and other potential materials may be even more effective. To be used on a large scale, though, these materials need to meet a few important requirements – they must be highly efficient, made from common chemical elements, and have low toxicity. So far, not many candidates have the potential to check all three of these boxes. Furthermore, studies into new materials are currently done by hand and are costly and time-consuming.

To speed up the discovery of these materials, the researchers created a unique robotic measurement system that’s able to perform photoabsorption spectroscopy, optical microscopy, and time-resolved microwave conductivity analyses. They then used the robot to evaluate 576 different thin-film semiconductor samples.

"Current solar cells are made of inorganic semiconductors containing silicon and gallium, but next-generation solar cells need to reduce both cost and weight," explains lead author Chisato Nishikawa. "Safety is also a concern; perovskite solar cells are efficient enough to rival silicon solar cells, but they contain toxic lead."

The samples tested in this study were all made from a varying blend of cesium, bismuth, tin, and iodine. They were also annealed at different temperatures and treated with different organic salt additives. To thoroughly characterize the material properties as well as automate the experimental process, the researchers also examined the data using artificial intelligence – specifically, machine learning.

"In recent years, machine learning has been very helpful in better understanding the properties of materials. These studies require vast amounts of experimental data, and combining automated experiments with machine-learning techniques is an ideal solution," says senior author Akinori Saeki.

The authors hope to automate even more of the process in the future, making it easier to examine completely new materials. As Nishikawa notes, "This method is ideal for exploring areas where there's no existing data."

The research team have had promising results with their robotic system so far. The measurement process is both fully automated and highly accurate, allowing work to be completed in one-sixth of the usual time needed.

The automated system makes the task of finding efficient and non-toxic solar materials considerably easier. With the help of robots and AI, the future of solar energy may be closer than we realize.

 

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The article, "Exploration of Solution-Processed Bi/Sb Solar Cells by Automated Robotic Experiments Equipped with Microwave Conductivity," will be published in JACS Au at DOI: https://doi.org/10.1021/jacsau.3c00519

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JOURNAL

JACS Au

DOI

10.1021/jacsau.3c00519 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Exploration of Solution-Processed Bi/Sb Solar Cells by Automated Robotic Experiments Equipped with Microwave Conductivity

(a) Illustration of an automated measurement system. (b) Examples of photoabsorption (PA), photoluminescence (PL), microwave conductivity, and optical microscope image data.

(a) Pictures of ~500 film samples on quartz substrates subjected to the automated measurements. (b) Bar chart of power conversion efficiencies of control and newly processed Cs-Bi-Sb-I solar cells.

CREDIT

Akinori Saeki

 

HKU astrophysicists collaborates with NASA’s IXPE telescope untangles theories surrounding historic supernova remnant

Peer-Reviewed Publication

THE UNIVERSITY OF HONG KONG

 

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THE FIGURE SHOWS A COMPOSITE IMAGE OF SUPERNOVA REMNANT SN 1006. THE UPPER LEFT CIRCLE SHOWS THE IXPE OBSERVED AREA. THE IXPE 2—4 KEV EMISSION IS SHOWN WITH THE PURPLE COLOUR, WITH MAGNETIC FIELD ORIENTATION DENOTED WITH WHITE LINES. THE RED AND WHITE REPRESENT THE SOFT AND HARD X-RAY EMISSION, RESPECTIVELY, TAKEN WITH THE CHANDRA X-RAY OBSERVATORY. THE GOLDEN COLOUR DENOTES THE SPITZER INFRARED EMISSION.

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CREDIT: X-RAY: CHANDRA: NASA/CXC/SAO, IXPE: NASA/MSFC/P. ZHOU ET AL.; INFRARED: SPITZER.

A team of international scientists, including Drs Stephen NG and Yi-Jung YANG from the Department of Physics at The University of Hong Kong (HKU), collaborated with NASA on research led by Nanjing University, utilising NASA’s IXPE (Imaging X-ray Polarimetry Explorer) telescope to capture the first polarised X-ray imagery of the supernova remnant SN 1006. The new results expand scientists’ understanding of the relationship between magnetic fields and the flow of high-energy particles from exploding stars. The discovery has been published in esteemed Scientific Journal The Astrophysical Journal. 

‘Magnetic fields are extremely difficult to measure, but IXPE provides an efficient way for us to probe them,’ said Dr Ping ZHOU, an astrophysicist at Nanjing University in Jiangsu, China, and lead author of the new paper on the findings. ‘Now we can see that SN 1006’s magnetic fields are turbulent but also present an organised direction.’ 

Situated some 6,500 light-years from Earth in the Lupus constellation, SN 1006 is all that remains after a titanic explosion, which occurred either when two white dwarfs merged or when a white dwarf pulled too much mass from a companion star. Initially spotted in the spring of 1006 CE by observers across China, Japan, Europe, and the Arab world, its light was visible to the naked eye for at least three years. Modern astronomers still consider it the brightest stellar event in recorded history.

Since modern observation began, researchers have identified the remnant’s strange double structure, markedly different from other rounded supernova remnants. It also has bright “limbs” or edges identifiable in the X-ray and gamma-ray bands. 

‘IXPE is a unique instrument. It can detect polarised X-rays, directly probing magnetic field structures in regions very close to the shock front, where high-energy particles are freshly accelerated. Such information is not available from any other telescopes,’ said Dr Stephen NG, a high-energy astrophysicist at the Department of Physics at HKU.

‘Close-proximity, X-ray-bright supernova remnants such as SN 1006 are ideally suited to IXPE measurements, given IXPE’s combination of X-ray polarisation sensitivity with the capability to resolve the emission regions spatially,’ said Dr Douglas SWARTZ, a researcher based at NASA’s Marshall Space Flight Center in Huntsville, Alabama, through the Universities Space Research Association. ‘This integrated capability is essential to localising cosmic-ray acceleration sites.’

Previous X-ray observations of SN 1006 offered the first evidence that supernova remnants can radically accelerate electrons and helped identify rapidly expanding nebulae around exploded stars as a birthplace for highly energetic cosmic rays, which can travel at nearly the speed of light. Scientists surmised that SN 1006’s unique structure is tied to the orientation of its magnetic field and theorised that supernova blast waves in the northeast and southwest move in the direction aligned with the magnetic field and more efficiently accelerate high-energy particles.

‘IXPE’s new findings helped validate and clarify those theories,’ said Dr Yi-Jung YANG, co-author of the paper and a high-energy astrophysicist at the Department of Physics of HKU, as well as a member of HKU Laboratory for Space Research. ‘The polarisation properties obtained from our spectral-polarimetric analysis align remarkably well with outcomes from other methods and X-ray observatories, underscoring IXPE’s reliability and strong capabilities,’ Yang said. ‘For the first time, we can map the magnetic field structures of supernova remnants at higher energies with enhanced detail and accuracy – enabling us to better understand the processes driving the acceleration of these particles.’

Researchers say the results demonstrate a connection between the magnetic fields and the remnant’s high-energy particle outflow. The magnetic fields in SN 1006’s shell are somewhat disorganised, per IXPE’s findings, yet still have a preferred orientation. As the shock wave from the original explosion goes through the surrounding gas, the magnetic fields become aligned with the shock wave’s motion. Charged particles are trapped by the magnetic fields around the original point of the supernova blast, where they quickly receive bursts of acceleration. Those speeding high-energy particles, in turn, transfer energy to keep the magnetic fields strong and turbulent. 

IXPE has observed three supernova remnants – Cassiopeia A, Tycho and now SN 1006 – since launching in December 2021, helping scientists develop a more comprehensive understanding of the origin and processes of the magnetic fields surrounding these phenomena. 

Scientists were surprised to find that SN 1006 is more polarised than the other two supernova remnants but that all three show magnetic fields oriented such that they are pointing outward from the centre of the explosion. As researchers continue to explore IXPE data, they are re-orienting their understanding of how particles get accelerated in extreme objects like these.

IXPE is a collaboration between NASA and the Italian Space Agency with partners and science collaborators in 12 countries. IXPE is led by NASA’s Marshall Space Flight Center in Huntsville, Alabama. Ball Aerospace, headquartered in Broomfield, Colorado, manages spacecraft operations together with the University of Colorado’s Laboratory for Atmospheric and Space Physics in Boulder.

This news release was adapted from the original version from NASA.
The research paper can be accessed at the following link: 
https://iopscience.iop.org/article/10.3847/1538-4357/acf3e6

Image and caption for download: https://www.scifac.hku.hk/press

For media enquiries, please contact Ms Casey To, External Relations Officer (tel: 39174948; email: caseyto@hku.hk / Ms Cindy Chan, Assistant Director of Communications of HKU Faculty of Science (tel: 3917 5286; email: cindycst@hku.hk).

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JOURNAL

The Astrophysical Journal

DOI

10.3847/1538-4357/acf3e6 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Magnetic Structures and Turbulence in SN 1006 Revealed with Imaging X-Ray Polarimetry

ARTICLE PUBLICATION DATE

27-Oct-2023

 

The importance of the Earth’s atmosphere in creating the large storms that affect satellite communications

Peer-Reviewed Publication

NAGOYA UNIVERSITY

 

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THE IMPORTANCE OF THE EARTH’S ATMOSPHERE IN CREATING THE LARGE STORMS THAT AFFECT SATELLITE COMMUNICATIONS

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CREDIT: ERG SCIENCE TEAM

A study from an international team led by researchers from Nagoya University in Japan and the University of New Hampshire in the United States has revealed the importance of the Earth’s upper atmosphere in determining how large geomagnetic storms develop. Their findings reveal the previously underestimated importance of the Earth’s atmosphere. Understanding the factors that cause geomagnetic storms is important because they can have a direct impact on the Earth’s magnetic field such as causing unwanted currents in the power grid and disrupting radio signals and GPS. This research may help predict the storms that will have the greatest consequences. 

Scientists have long known that geomagnetic storms are associated with the activities of the Sun. Hot charged particles make up the Sun's outer layer, the one visible to us. These particles flow out of the Sun creating the ‘solar wind’, and interact with objects in space, such as the Earth. When the particles reach the magnetic field surrounding our planet, known as the magnetosphere, they interact with it. The interactions between the charged particles and magnetic fields lead to space weather, the conditions in space that can affect the Earth and technological systems such as satellites.  

An important part of the magnetosphere is the magnetotail. The magnetotail is the part of the magnetosphere that extends away from the Sun, in the direction of the solar wind flow. Inside the magnetotail is the plasma sheet region, which is full of charged particles (plasma). The plasma sheet is important because it is the source region for the particles that get into the inner magnetosphere, creating the current that causes geomagnetic storms.   

Although the importance of the Sun is well known, an international group of researchers aimed to solve the mystery of how much of the plasma in the magnetosphere comes from Earth and how that contribution changes during a geomagnetic storm. The group was led by Lynn Kistler, Nagoya University  Designated Professor and University of New Hampshire Professor (cross-appointment),  Yoshizumi Miyoshi, Nagoya University Professor, and Tomoaki Hori, Nagoya University Designated Professor. For their study, they used data from a large geomagnetic storm that happened on September 7-8, 2017. During this time, the Sun released a massive coronal mass ejection that collided with the Earth's atmosphere, resulting in a huge geomagnetic storm. The impact disrupted the magnetosphere, leading to interference with radio signals, GPS, and precision timing applications.  

The researchers retrospectively analyzed the ion transport during this event using data from several space missions, including the NASA/Magnetospheric Multiscale (MMS) mission, the Japanese Arase mission, the ESA/Cluster mission, and the NASA/Wind mission. They distinguished the ions from those of the solar wind and from those of the ionosphere itself.  

Using simultaneous measurements of the solar wind composition to track the source changes, they identified substantial changes in the composition and other properties of the near-earth plasma sheet as it developed. These properties of the plasma sheet, such as density, particle energy distribution, and composition, affect the development of the geomagnetic storm. 

At the start of the main phase of the storm, the source changed from solar wind dominated to ionosphere dominated. “The most important discovery was that at the beginning of the geomagnetic storm, the plasma changed from mostly solar to mostly ionospheric,” explained Kistler. “This shows that the geomagnetic storm drives more outflow from the Earth’s ionosphere, and that the ionospheric plasma can move quickly throughout the magnetosphere.”  

“Overall, our research contributes to understanding the development of geomagnetic storms by showing the importance of Earth’s ionospheric plasma,” she continues. “We found compelling evidence that plasmas from not only the Sun but also the Earth drive a geomagnetic storm. In short, the properties of the plasma sheet (the density, the particle energy distribution, the composition) will affect geomagnetic storms, and these properties are different for different sources.” 

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Nagoya University has a history of about 150 years and has been pursuing excellence since its founding. Six of the 18 Japanese Nobel Prize-winners since 2000 did all or part of their work at Nagoya University. A number of other important discoveries have also been made at the University, including the Okazaki DNA Fragments by Reiji and Tsuneko Okazaki, and depletion forces by Sho Asakura and Fumio Oosawa. 

The University of New Hampshire inspires innovation and transforms lives in our state, nation and world. More than 16,000 students from all 49 states and 82 countries engage with an award-winning faculty in top-ranked programs in business, engineering, law, health and human services, liberal arts and the sciences across more than 200 programs of study. A Carnegie Classification R1 institution, UNH partners with NASA, NOAA, NSF, and NIH, and received over $210 million in competitive external funding in FY23 to further explore and define the frontiers of land, sea and space. 

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JOURNAL

Nature Communications

DOI

10.1038/s41467-023-41735-3