Gut hormones play an important role in regulating fat production in the body. One key hormone, released a few hours after eating, turns off fat production by regulating gene expression in the liver, but this regulation is abnormal in obesity, researchers at the University of Illinois Urbana-Champaign found in a new study.
The study, led by molecular and integrative physiology professor Jongsook Kim Kemper and research scientist Young-Chae Kim, was published in the journal Nature Communications.
After eating, the pancreas produces insulin, which triggers the liver to convert digested foods into fat for storage in a process known as lipogenesis. A few hours later, when the body begins the transition to fasting mode, the liver slows fat production. While the insulin pathway has been thoroughly studied, the pathway by which lipogenesis is turned off has largely remained unknown, Kemper said.
In the new study, Kemper’s team found that the gut hormone FGF15 in mice and its human counterpart FGF19 turn off fat-producing genes in the liver. The hormones are released a few hours after eating, when the body transitions from feeding to fasting. FGF15/19 activate regulatory molecules to enter the nucleus, the center of the cell where DNA is stored, and inhibit gene expression.
“This gut hormone actually acts as a breaker of insulin action, and specifically inhibits lipogenesis in the liver so that it’s tightly regulated,” Kemper said. “For example, with the holidays coming up, if you eat some cookies, the body will release insulin, which promotes lipogenesis. If lipogenesis is not reduced later when the body enters the fasting state, excess fat will accumulate in the liver, so the FGF19 hormone puts the brakes on fat production.”
Furthermore, in experiments involving mice with obesity and human patients with nonalcoholic fatty liver disease, the researchers found that the pathway for turning off fat production was dysregulated. The genes that the gut hormone regulates were highly active, the FGF15/19-activated regulatory molecules did not even enter the cell’s nucleus and the suppression markers were not added to the genes.
“This study could be very important for understanding this pathway and investigating how it is abnormal in obesity and nonalcoholic fatty liver disease,” Kemper said. “It adds to our understanding of obesity, nonalcoholic fatty liver disease and other metabolic disorders. It also could have implications for other diseases such as diabetes or certain cancers, for which obesity is a risk factor.
“Based on this study, we potentially could search for therapeutic treatment options to target this pathway and increase regulatory function.”
The American Heart Association and the National Institutes of Health supported this work.
References: Kim, YC., Seok, S., Zhang, Y. et al. Intestinal FGF15/19 physiologically repress hepatic lipogenesis in the late fed-state by activating SHP and DNMT3A. Nat Commun 11, 5969 (2020). https://doi.org/10.1038/s41467-020-19803-9
Findings reveal the early events that take place during tuberculosis infection, and provide a model for future research into respiratory and other infections.
Scientists have developed a lung-on-chip model to study how the body responds to early tuberculosis (TB) infection, according to findings published today in eLife.
TB is a disease caused by the bacterium Mycobacterium tuberculosis (M. tuberculosis) and most often affects the lungs. The model reveals that respiratory system cells, called alveolar epithelial cells, play an essential role in controlling early TB infection. They do this by producing a substance called surfactant – a mixture of molecules (lipids and proteins) that reduce the surface tension where air and liquid meet in the lung.
These findings add to our understanding of what happens during early TB infection, and may explain in part why those who smoke or have compromised surfactant functionality have a higher risk of contracting primary or recurrent infection.
TB is one of the world’s top infectious killers and affects people of all ages. While it mostly affects adults, there are currently no effective vaccines available to this group. This is partly due to challenges with studying the early stages of infection, which take place when just one or two M. tuberculosis bacteria are deposited deep inside the lung.
“We created the lung-on-chip model as a way of studying some of these early events,” explains lead author Vivek Thacker, a postdoctoral researcher at the McKinney Lab, École polytechnique fédérale de Lausanne (EPFL), Lausanne, Switzerland. “Previous studies have shown that components of surfactant produced by alveolar epithelial cells can impair bacterial growth, but that the alveolar epithelial cells themselves can allow intracellular bacterial growth. The roles of these cells in early infection are therefore not completely understood.
“We used our model to observe where the sites of first contact are, how M. tuberculosis grows in alveolar epithelial cells compared to bacteria-killing cells called macrophages, and how the production of surfactant affects growth, all while maintaining these cells at the air-liquid interface found in the lung.”
The team used their lung-on-chip model to recreate a deficiency in surfactant produced by alveolar epithelial cells and then see how the lung cells respond to early TB infection. The technology is optically transparent, meaning they could use an imaging technique called time-lapse microscopy to follow the growth of single M. tuberculosis bacteria in either macrophages or alveolar epithelial cells over multiple days.
Their studies revealed that a lack of surfactant results in uncontrolled and rapid bacterial growth in both macrophages and alveolar epithelial cells. On the other hand, the presence of surfactant significantly reduces this growth in both cells and, in some cases, prevents it altogether.
“Our work shines a light on the early events that take place during TB infection and provides a model for scientists to build on for future research into other respiratory infections,” says senior author John McKinney, Head of the Laboratory of Microbiology and Microtechnology at EPFL. “It also paves the way for experiments that increase the complexity of our model to help understand why some TB lesions progress while others heal, which can occur at the same time in the same patient. This knowledge could one day be harnessed to develop effective new interventions against TB and other diseases.”
The authors add that they are currently using a human lung-on-chip model to study how our lungs may respond to a low-dose infection and inoculation of SARS-CoV-2, the virus that causes COVID-19.
The magic of mathematics is particularly reflected in magic squares. Recently, quantum physicist Gemma De las Cuevas and mathematicians Tim Netzer and Tom Drescher introduced the notion of the quantum magic square, and for the first time studied in detail the properties of this quantum version of magic squares. Magic squares belong to the imagination of humanity for a long time. The oldest known magic square comes from China and is over 2000 years old. One of the most famous magic squares can be found in Albrecht Dürer’s copper engraving Melencolia I. Another one is on the facade of the Sagrada Família in Barcelona. A magic square is a square of numbers such that every column and every row sums to the same number. For example, in the magic square of the Sagrada Família every row and column sums to 33.
If the magic square can contain real numbers, and every row and column sums to 1, then it is called a doubly stochastic matrix. One particular example would be a matrix that has 0’s everywhere except for one 1 in every column and every row. This is called a permutation matrix. A famous theorem says that every doubly stochastic matrix can be obtained as a convex combination of permutation matrices. In words, this means that permutation matrices “contain all the secrets” of doubly stochastic matrices—more precisely, that the latter can be fully characterised in terms of the former.
In a new paper in the Journal of Mathematical Physics, Tim Netzer and Tom Drescher from the Department of Mathematics and Gemma De las Cuevas from the Department of Theoretical Physics have introduced the notion of the quantum magic square, which is a magic square but instead of numbers one puts in matrices. This is a non-commutative, and thus quantum, generalisation of a magic square. The authors show that quantum magic squares cannot be as easily characterised as their “classical” cousins. More precisely, quantum magic squares are not convex combinations of quantum permutation matrices. “They are richer and more complicated to understand”, explains Tom Drescher. “This is the general theme when generalisations to the non-commutative case are studied.”
“The work is at the intersection of algebraic geometry and quantum information and showcases the benefits of interdisciplinary collaboration”, say Gemma De las Cuevas and Tim Netzer.
Memory is as much about the future as it is the past.
Whether experiencing something new, or something we’ve experienced a hundred times, people use memories of the past to navigate subsequent encounters. Traditionally, psychologists believed that the more ingrained a memory of something was, the more difficult it would be to update your understanding of that thing, should it change.
New research from Washington University in St. Louis finds, however, the opposite is true. In a paper published Nov. 20 in PNAS, Jeffrey Zacks, professor and associate chair of the Department of Psychological & Brain Sciences in Arts & Sciences and professor of radiology in the School of Medicine, found the stronger a memory is first encoded, the easier it is for a person to notice subsequent changes and to integrate them into their updated understanding.
“The bigger the discrepancy is between a previous memory and what happens the next time,” Zacks said, “the stronger the signal is that you need to update your memory representation.”
Results of the study also suggested that in older adults, a weaker ability to discern that one event differs from a previous memory may be partially responsible for a decline in memory function.
In the experiment, two groups of participants were tested — younger adults, ages 18-27, and older adults, ages 65-84. Over two days, participants had their brains scanned using MRI while they watched and answered questions about movies that represented a day in an actor’s life.
Some of the activities changed from day to day. For example, on Day One, the actor might unroll a yoga mat and do some stretches. On Day Two, the movie might begin the same; the actor might pull out a yoga mat. Then, however, they could do one of two things: either the same stretch routine or abdominal crunches.
While participants watched the movie of Day Two, after the actor had unrolled the mat, the researchers paused the movie and asked participants to remember what happened in the second half of the previous day’s movie. They analyzed the MRI signal during this phase to quantify the degree to which their brains were able to reinstate patterns formed when watching the original ending. Then the second movie continued — showing either the previous ending or the changed one.
Three days later, participants were asked to remember what happened in the second movie, and whether or not it was different from the first.
Classical memory theory would suggest the stronger a person encoded the first movie, the more it would interfere with the conflicting information on the second day if the actor had done something different.
However, researchers saw the opposite. When viewers showed more reinstatement of brain activity patterns from Day One endings while watching Day Two, they were more likely to notice a difference in the second movie.
This illustrated memory retrieval was happening in real time, Zacks said. When people were watching the second movie, they weren’t just encoding it, or forming new memories, “They were retrieving what had happened in the first movie as they watched the second movie, integrating the two, and utilizing retrieval to guide comprehension.”
Performance differences between age groups
When it came to differences in performance between the two different age groups, older adults had somewhat poorer memory overall. But it wasn’t as though the older adults were unable on Day Two to recall what they had seen on Day One. More striking was the relationship between their objective retrieval, measured from the brain and from their responses, and their self-awareness of their memory.
On Day Two, after being asked to remember the previous film, participants would indicate their confidence in being able to predict what would happen next, based on what they had seen on Day One. When they were shown a different ending on Day Two, however, the older participants were more likely to say that both movies unfolded identically.
While both the older and younger adults made errors, older adults were more likely to be confident that they hadn’t made an error, whether or not their memory responses and brain activity indicated that they had actually remembered. Younger adults’ self-reporting more closely mirrored their actual performance.
So why did the older participants remain confident, despite their poorer performance? While this study did not consider that question directly, Zacks has some ideas, based on a theoretical framework designed by Larry Jacoby, professor emeritus of psychological and brain sciences.
In short, Jacoby’s model said people draw from multiple sources of information when trying to remember an event. Some of that is specific, acute information: the color or texture of your favorite pillow, for example. Others are more general, provoking more of a generic response without being tightly bound to a specific, situational feature.
That might explain some participants’ inability to distinguish between Day One and Day Two. Crunches or stretches (or planks or push ups, for that matter) on a yoga mat might all feel similar enough to provoke the same response, accounting for the older adults’ confidence in their memory.
When any of the participants — of either age group — wrongly predicted the outcome of the second movie, they were committing what psychologists usually think of as a “prediction error,” Zacks said. “They were making a prediction based on memory, but that prediction was violated,” he added. This study, however, shows there is at least some value in such errors; they can drive memory updates.
“If you look at how many psychologists behave, you’d think memory evolved so we could sit in armchairs and think about the past — but that doesn’t confer any selective advantage by itself,” he said. “We have memory so we can recall — the last time I went to the watering hole, the sabretooth came from my left, so I’m going to look left this time. But if this time it comes from my right, I’d better be able to update my representation. That is how you pass on your genes.”
References: David Stawarczyk, Christopher N. Wahlheim, Joset A. Etzel, Abraham Z. Snyder, Jeffrey M. Zacks, “Aging and the encoding of changes in events: The role of neural activity pattern reinstatement”, Proceedings of the National Academy of Sciences Nov 2020, 201918063; DOI: 10.1073/pnas.1918063117
Gemini North observations enable breakthrough in centuries-old effort to unravel astronomical mystery.
An international team of astronomers using Gemini North’s GNIRS instrument have discovered that CK Vulpeculae, first seen as a bright new star in 1670, is approximately five times farther away than previously thought. This makes the 1670 explosion of CK Vulpeculae much more energetic than previously estimated and puts it into a mysterious class of objects that are too bright to be members of the well-understood type of explosions known as novae, but too faint to be supernovae.
350 years ago, the French monk Anthelme Voituret saw a bright new star flare into life in the constellation of Vulpecula. Over the following months, the star became almost as bright as Polaris (the North Star) and was monitored by some of the leading astronomers of the day before it faded from view after a year . The new star eventually gained the name CK Vulpeculae and was long considered to be the first documented example of a nova — a fleeting astronomical event arising from an explosion in a close binary star system in which one member is a white dwarf, the remnant of a Sun-like star. However, a string of recent results have thrown the longstanding classification of CK Vulpeculae as a nova into doubt.
In 2015, a team of astronomers suggested that CK Vulpeculae’s appearance in 1670 was the result of two normal stars undergoing a cataclysmic collision. Just over three years later, the same astronomers further proposed that one of the stars was in fact a bloated red giant star, following their discovery of a radioactive isotope of aluminum in the immediate surroundings of the site of the 1670 explosion. Complicating the picture even further, a separate group of astronomers proposed a different interpretation. In their paper, also published in 2018, they suggested that the sudden brightening in 1670 was the result of the merger between a brown dwarf — a failed star too small to shine via thermonuclear fusion that powers the Sun — and a white dwarf.
Now, adding to the ongoing mystery surrounding CK Vulpeculae, new observations from the international Gemini Observatory, a Program of NSF’s NOIRLab, reveal that this enigmatic astronomical object is much farther away and has ejected gas at much higher speeds than previously reported.
This team, led by Dipankar Banerjee of Physical Research Laboratory Ahmedabad, India, Tom Geballe of Gemini Observatory, and Nye Evans of Keele University in the United Kingdom, initially planned to use the Gemini Near-Infrared Spectrograph (GNIRS) instrument on Gemini North on Hawai’i’s Maunakea to confirm the 2018 detection of radioactive aluminum at the heart of CK Vulpeculae . After realizing that detecting this in the infrared would be far more difficult than they originally thought, the astronomers improvised and obtained infrared observations across the full extent of CK Vulpeculae, including the two wisps of nebulosity at its outermost edges.
“The key to our discovery was the GNIRS measurements obtained at the outer edges of the nebula,” elaborated Geballe. “The signature of redshifted and blueshifted iron atoms detected there shows that the nebula is expanding much more rapidly than previous observations had suggested.” 
Credit: Images and videos: International Gemini Observatory/NOIRLab/NSF/AURA, K. Pu’uohau-Pummill,A. M. Geller/Northwestern University/CTIO/SOAR. Image processing: Travis Rector (University of Alaska Anchorage), Mahdi Zamani & Davide de Martin. Music: zero-project – The Lower Dungeons (https://www.zero-project.gr/).
As lead author and astronomer Banerjee explains further, “We did not suspect that this is what we would find. It was exciting when we found some gas traveling at the unexpectedly high speed of about 7 million km/hour. This hinted at a different story about CK Vulpeculae than what had been theorized.”
By measuring both the speed of the nebula’s expansion and how much the outermost wisps had moved during the last ten years, and accounting for the tilt of the nebula on the night sky, which had been estimated earlier by others, the team determined that CK Vulpeculae lies approximately 10,000 light-years distant from the Sun — about five times as far away as previously thought. That implies that the 1670 explosion was far brighter, releasing roughly 25 times more energy than previously estimated . This much larger estimate of the amount of energy released means that whatever event caused the sudden appearance of CK Vulpeculae in 1670 was far more violent than a simple nova.
“In terms of energy released, our finding places CK Vulpeculae roughly midway between a nova and a supernova,” commented Evans. “It is one of a very few such objects in the Milky Way and the cause — or causes — of the outbursts of this intermediate class of objects remain unknown. I think we all know what CK Vulpeculae isn’t, but no one knows what it is.”
The visual appearance of the CK Vulpeculae nebula and the high velocities observed by the team could help astronomers to recognize relics of similar events — in our Milky Way or in external galaxies — that have occurred in the past.
“It is difficult at this stage to offer a definitive or compelling explanation for the origin of the 1670 eruption of CK Vulpeculae,” concluded Banerjee. “Even 350 years after Voituret’s discovery, the nature of the explosion remains a mystery. “
 17th-century astronomers who observed the bright new star CK Vulpeculae included distinguished Polish mayor, brewer, and astronomer Johannes Hevelius and the French-Italian astronomer Giovanni Domenico Cassini, who discovered four of Saturn’s moons. After it faded from view in 1671 there were numerous unsuccessful attempts through the intervening centuries to recover it, some by noted astronomers including Halley, Pickering and Humason.
 A spectrograph is an instrument that splits light from an astronomical object into its component wavelengths, allowing the composition of the gas emitting the light, its speed, and other traits to be measured.
 Just as the pitch of an ambulance siren changes depending on whether the vehicle is moving towards or away from you, astronomical objects change color depending on whether they are moving towards or away from an observer. Objects moving away from Earth become redder (known as redshift) and approaching objects become bluer (known as blueshift).
 The brightness of an object is inversely proportional to the square of the distance from an observer. In the case of CK Vulpeculae, if the 1670 explosion occurred five times as far away it must have been 52 = 25 times as bright.
New findings from UC uncover clues into why immunotherapy works for some and not others with head and neck cancer.
University of Cincinnati researchers have discovered new clues into why some people with head and neck cancer respond to immunotherapy, while others don’t.
Findings published in the Journal for ImmunoTherapy of Cancer show that it could all come down to “channeling” the power and function within one particular type of immune cell.
Laura Conforti, PhD, professor in the Department of Internal Medicine at the UC College of Medicine and corresponding author on the study, says understanding these mechanisms could help in creating combination treatments to more effectively treat some patients with cancer.
She points out that head and neck cancers are the sixth most common cancers in the world, affecting about 53,000 Americans every year. To combat the deadly disease, doctors often turn to immunotherapy, which boosts the body’s own immune system in an effort to identify and kill cancer cells.
“Our immune cells are naturally programmed to distinguish between our body’s ‘normal’ cells and what they see as ‘foreign’ cells and attack only the foreign cells,” explains Conforti.
She says the immune cells — called T cells — lead the body’s attack against cancers but the impact of that attack can be proven futile if a molecule in cancer cells is able to bind to an immune checkpoint in the T cells and effectively “turn them off like a light switch.” As a result, the T cells leave the cancer cells alone, which Conforti says is “a major problem,” especially for head and neck cancers.
A known immunotherapy treatment (pembrolizumab) targets the checkpoint molecule and blocks the “off switch” of the T cells, but scientists are trying to determine why this method works in some people and not in others.
Conforti further explains that the ability of these T cells to attack and destroy cancer cells relies on molecules called potassium ion channels, which are present in T cells and are responsible for a variety of functions, including killing cancer cells.
Conforti’s team includes co-lead authors Hannah Newton, PhD, a recent UC doctoral graduate; Vaibhavkumar Gawali, PhD, postdoctoral fellow; and Ameet Chimote, PhD, research scientist in Conforti’s lab.
The team found that when patients with head and neck cancer were given immunotherapy at UC Medical Center, T cells in these patients showed increased activity in these channels, allowing them to more effectively reach the cancer cells and kill them.
The team also found that after the treatment was delivered to patients, these channels in the T cells circulating in their blood were more active, meaning they were more equipped to continue fighting off the cancerous cells.
“We also saw that head and neck cancer patients who were responding to this immunotherapy, meaning their tumors were shrinking, had greater channel activity in their T cells soon after treatment, and the T cells had more ability to enter into the tumors to continue killing cancer cells,” Conforti adds. “However, patients who did not respond lacked this increased activity.
“Immunotherapy is not one-size-fits all, since some patients respond to immunotherapy, while others don’t, but our research shows that ion channels within T cells of these patients play a crucial role in the response of immunotherapy. Now that we know the benefits of these channels, more research is needed to look at ways we can activate them or create combination therapies to help patients increase their chance of survival.”
Team member Newton, who recently completed her doctorate at UC and is now working at the National Institutes of Health-sponsored Frederick National Laboratory for Cancer Research, says that working on this study at UC was invaluable.
“This research allowed me to collaborate with diverse professional individuals including medical oncologists, clinical coordinators and other researchers and gave me the opportunity to better understand the bench-to-bedside procedure for drug development,” Newton says. “Most importantly, it could help clinicians determine more personalized and effective treatment combinations for patients with head and neck cancer.”
The only dinosaur bones ever found on the island of Ireland have been formally confirmed for the first time.
The only dinosaur bones ever found on the island of Ireland have been formally confirmed for the first time by a team of experts from the University of Portsmouth and Queen’s University Belfast, led by Dr Mike Simms, a curator and palaeontologist at National Museums NI.
The two fossil bones were found by the late Roger Byrne, a schoolteacher and fossil collector, who donated them along with many other fossils to Ulster Museum. Analysis has confirmed they are from early Jurassic rocks found in Islandmagee, on the east coast of County Antrim.
Ulster Museum has announced plans to put them on display when it reopens after the latest rounds of restrictions are lifted.
Dr Simms, National Museums NI, said: “This is a hugely significant discovery. The great rarity of such fossils here is because most of Ireland’s rocks are the wrong age for dinosaurs, either too old or too young, making it nearly impossible to confirm dinosaurs existed on these shores. The two dinosaur fossils that Roger Byrne found were perhaps swept out to sea, alive or dead, sinking to the Jurassic seabed where they were buried and fossilised.”
The article, published in the Proceedings of the Geologists’ Association, is part of a larger project to document Jurassic rocks in Northern Ireland and draws on many fossils in Ulster Museum’s collections.
Originally it was assumed the fossils were from the same animal, but the team were surprised to discover that they were from two completely different dinosaurs. The study, employing the latest available technology, identified the type of dinosaur from which each came. One is part of a femur (upper leg bone) of a four-legged plant-eater called Scelidosaurus. The other is part of the tibia (lower leg bone) of a two-legged meat-eater similar to Sarcosaurus.
The University of Portsmouth team, researcher Robert Smyth, originally from Ballymoney, and Professor David Martill, used high-resolution 3D digital models of the fossils, produced by Dr Patrick Collins of Queen’s University Belfast, in their analysis of the bone fragments.
Robert Smyth said: “Analysing the shape and internal structure of the bones, we realised that they belonged to two very different animals. One is very dense and robust, typical of an armoured plant-eater. The other is slender, with thin bone walls and characteristics found only in fast-moving two-legged predatory dinosaurs called theropods.”
“Despite being fragmentary, these fossils provide valuable insight on a very important period in dinosaur evolution, about 200 million years ago. It’s at this time that dinosaurs really start to dominate the world’s terrestrial ecosystems.”
Professor Martill said: “Scelidosaurus keeps on turning up in marine strata, and I am beginning to think that it may have been a coastal animal, perhaps even eating seaweed like marine iguanas do today.”
The Denmark Expedition set out to explore unknown Inuit land in 1906. Three members died.
Jørgen Brønlund was one of the participants in the legendary Mylius Erichsen’s Denmark Expedition to Greenland 1906-08. In 1907, he died in a small cave of hunger and frostbite, but before that, he made one last note in his diary:
“Perished 79 Fjord after trying to return home over the ice sheet, in November Month I come here in waning moonlight and could not continue from Frost in the Feet and the Dark”.
The Danish expedition had traveled to Northeast Greenland the year before to explore and map the most northerly Greenland and also to determine whether the 50,000 square kilometer Peary Land was a peninsula or an island. If an island, it would accrue to the Americans. If a peninsula, it would be part of Danish territory.
It was after a failed attempt to get into the Independence Fjord that Jørgen Brønlund and two other participants on the expedition’s sled team 1 eventually had to give up.
A few days before Brønlund died, the two others from sled team 1 died: Expedition commander Mylius Erichsen and Niels Peter Høegh Hagen. Neither their corpses nor diaries have since been found.
Jørgen Brønlund’s body and diary were found, and almost ever since, the diary has been kept at the Royal Library in Copenhagen.
Now chemists from the University of Southern Denmark have had the opportunity to analyze a very specific part of the diary’s last page; more specifically, a black spot below Jørgens Brønlund’s last entry and signature.
The results are published in the journal Archaeometry.
The analyzes reveal that the spot consists of the following components: burnt rubber, various oils, petroleum and feces.
This new knowledge gives a unique insight into Brønlund’s last hours, says professor of chemistry, Kaare Lund Rasmussen, Department of Physics, Chemistry and Pharmacy at the University of Southern Denmark.
I see for me, how he, weakened and with dirty, shaking hands, fumbled in an attempt to light the burner, but failed, he says.
As a last survivor of sled team 1, Brønlund had reached a depot on Lambert’s Land and had at his disposal a LUX petroleum burner, matches and petroleum. But there was no metabolised alcohol to preheat the burner.
He had to find something else to get the burner going. You can use paper or oiled fabric, but it is difficult. We think he tried with the oils available, because the black spot contains traces of vegetable oil and oils that may come from fish, animals or wax candles, says Kaare Lund Rasmussen.
The spot’s content of burnt rubber probably comes from a gasket in the Lux burner. The gasket may have been burned long before Brønlund’s crisis in the cave, but it may also have happened during his last vain attempt to light a fire.
Brønlund’s corpse and diary were found four months later, when spring came, by Johan Peter Koch and Tobias Gabrielsen, who had left Danmarkshavn to find the missing members of sled team 1.
The diary was found at Brønlund’s feet and was taken back to Denmark and is now kept at the Royal Library in Copenhagen.
Brønlund’s Lux burner was found in 1973 by the Danish Defense Sirius Patrol. After the re-burial of Brønlund in 1978, it was donated to the Arctic Institute in Copenhagen.
Peninsula in northeast Greenland, named after the American polar explorer R.E. Peary, who believed that the area was an island and thus not part of Denmark. This was disproved by the Denmark Expedition, and Peary Land remained Danish. Peary Land is uninhabited.
On November 18 scientists from the US National Science Foundation’s National Solar Observatory predicted the arrival of a large sunspot just in time for Thanksgiving. Using a special technique called helioseismology, the team has been “listening” to changing sound waves from the Sun’s interior which beckon the arrival of a large sunspot. Recent changes in these sound waves pointed to the imminent appearance of new sunspots which we can now see from Earth near the eastern solar limb.
“We measured a change in acoustic signals on the far-side of the Sun”, explains Dr. Alexei Pevtsov, Associate Director for NSO’s Integrated Synoptic Program, the program responsible for the prediction. “We can use this technique to identify what is happening on the side of the Sun that faces away from Earth days before we can catch a glimpse from here. Having up to five days lead time on the presence of active sun spots is extremely valuable to our technology-heavy society.”
Solar storms often originate in sunspot regions, especially if the sunspot is large and complicated. The more tangled the magnetic field, the more likely it will result in large solar flares and coronal mass ejections which in turn can result in space weather effects at Earth. These include impacts on communications, GPS and possibly electrical grid systems. NSO provides 24/7 “eyes on the Sun” through the NSF-funded GONG network. The network consists of six monitoring stations positioned across the globe, observing the Sun’s magnetic field and other features all day every day.
“The ability of GONG to identify and track active regions emergent on the far side of the Sun has important implications for future space weather predictive capabilities” said Dr. Carrie Black, Program Director at NSF. “GONG continues to be a valuable tool for both fundamental science research and operations.”
Dr. Kiran Jain, the scientist who is leading the far side prediction at NSO, describes the evolution of the sunspot as “the strongest far-side signal we have had this solar cycle. We first noticed the signal in our far-side images on November 14, 2020,” she continues. “It was inconspicuous at first but grew quickly, breaking detection thresholds just one day later. Since we are in the very early phase of the new solar cycle, the signal from this large spot stands out clearly.”
The far-side maps use “helioseismology,” a technique developed by NSO scientists in the 1990s, to detect how sound waves interact with the Sun’s interior structure, especially magnetic fields.
Seismology here on Earth measures sound waves traveling through Earth’s interior to reveal what we cannot see beneath the Earth’s surface. Similarly, helio-seismology can highlight structures on the Sun that cannot yet be seen from Earth. Millions of sound frequencies bounce freely throughout the Sun’s interior, like a bell. Regions of strong magnetic fields perturb with these sound waves, thus a change in wave signal measurements indicates that sunspots may be present.
“The GONG network is providing an essential service to United States space weather preparedness” explains Dr. Valentin Martinez Pillet, Director of the National Solar Observatory. “but it is close to three decades old and is in need of an upgrade. The original system was not created with space weather in mind, so we are exploring options for the Next Generation GONG network, with modern instrumentation specially attuned with space weather as a priority.”
The GONG measurements suggest the new sunspot has been growing since its first detection on the far side of the Sun late last week and is now finally visible from Earth where it will continue to be monitored by the GONG network and other solar observing assets. The sunspot will likely be visible using binoculars or small telescopes with appropriate solar filters later this week as it passes across the face of the Sun.