HEY DOUGH BOY

WWI helmets protect against shock waves just as well as modern designs

by Ken Kingery, Duke University

A French helmet from World War I and a modern helmet sit beneath a shock tube to test how well they protect the dummies underneath from a shock wave. The ridge down the center of the French helmet was designed for deflecting shrapnel, but may well have also helped deflect the shock wave, allowing the helmet to outperform even modern combat helmets. Credit: Duke University

iomedical engineers from Duke University have demonstrated that, despite significant advancements in protection from ballistics and blunt impacts, modern military helmets are no better at protecting the brain from shock waves created by nearby blasts than their World War I counterparts. And one model in particular, the French Adrian helmet, actually performed better than modern designs in protecting from overhead blasts.

The research could help improve the blast protection of future helmets through choosing different materials, layering multiple materials of different acoustic impedance, or altering their geometry.

The results appeared online on February 13 in the journal PLOS ONE.

"While we found that all helmets provided a substantial amount of protection against blast, we were surprised to find that the 100-year-old helmets performed just as well as modern ones," said Joost Op 't Eynde, a biomedical engineering PhD student at Duke and first author of the study. "Indeed, some historical helmets performed better in some respects." 

Researchers have only recently begun to study the brain damage a shock wave can cause on its own—and for good reason. Helmets were originally designed to protect from penetrating objects like bullets and shrapnel, and blast waves will kill through pulmonary trauma long before they cause even minor brain damage.

With the advent of body armor, however, soldiers' lungs are much more protected from such blasts than they used to be. This has caused the incidence of pulmonary trauma following a blast to drop far below that of brain or spine injuries in modern military conflicts, despite the difference in blast tolerance.

A high-speed video of a French helmet from World War I being bombarded by a shock wave designed to imitate a blast from German artillery shells a few meters away. Credit: Duke University

While there have been studies that suggest modern helmets provide a degree of protection from shock waves, no currently deployed helmet has been specifically designed for blast protection. And because soldiers today experiencing shock waves while wearing body armor aren't all that different from soldiers 100 years ago experiencing shock waves while in the trenches, Op 't Eynde decided to see if those old designs offered any lessons to be learned.

"This study is, to the best of our knowledge, the first to assess the protective capabilities of these historical combat helmets against blasts," said Op 't Eynde.

Working with Cameron "Dale" Bass, associate research professor of biomedical engineering at Duke, Op 't Eynde created a system to test the performance of World War I helmets from the United Kingdom/United States (Brodie), France (Adrian), Germany (Stahlhelm) and a current United States combat variant (Advanced Combat Helmet).

The researchers took turns placing different helmets on a dummy's head outfitted with pressure sensors at various locations. They then placed the head directly underneath a shock tube, which was pressurized with helium until a membrane wall burst, releasing the gas in a shock wave. The helmets were tested with shock waves of varying strength, each corresponding to a different type of German artillery shell exploding from a distance of one to five meters away.

The amount of pressure experienced at the crown of the head was then compared to brain injury risk charts created in previous studies. While all helmets provided a five-to-tenfold reduction in risk for moderate brain bleeding, the risk for someone wearing a circa-1915 French "Adrian" helmet was less than for any of the other helmets tested, including the modern advanced combat helmet.

Test results show that for the peak pressure experienced by the crown of the dummy's head for each helmet, the French Adrian helmet outperforms the rest. Credit: Duke University

"The result is intriguing because the French helmet was manufactured using similar materials as its German and British counterparts, and even had a thinner wall," said Op 't Eynde. "The main difference is that the French helmet had a crest on top of its crown. While it was designed to deflect shrapnel, this feature might also be deflecting shock waves."

t also might be that, because the pressure sensor was mounted directly under the crest, the crest provided an additional first layer for reflecting the shock wave. And the French helmet did not show the same advantage in pressure sensors at any other location. For locations such as the ears, performance seemed to be dictated by the width of the helmet's brim and just how much of the head it actually covered.

As for the modern helmet, Op 't Eynde theorizes that its layered structure might be important in its performance. Because a shock wave is reflected every time it encounters a new material with a different acoustic impedance, the layered structure of the modern helmet might contribute to its blast protection.

But no matter which helmet was tested, the results clearly indicated that helmets might play an especially important role in protecting against mild blast-induced brain trauma. According to the researchers, this finding alone shows the importance of continuing this type of research to design helmets that can better absorb shock waves from nearby overhead explosions.

"The difference a simple crest or a wider brim can make in blast protection, shows just how important this line of research could be," said Op 't Eynde, who initially came to Duke on a scholarship from the Belgian American Educational Foundation, which was established with funds from American relief efforts in Belgium during World War I. "With all of the modern materials and manufacturing capabilities we possess today, we should be able to make improvements in helmet design that protects from blast waves better than helmets today or 100 years ago."Material for safer football helmets may reduce head injuries

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More information: Joost Op 't Eynde et al. Primary blast wave protection in combat helmet design: A historical comparison between present day and World War I, PLOS ONE (2020). DOI: 10.1371/journal.pone.0228802

Shell staff say they are ‘deeply concerned’ by shift from green energy in open letter to chief

James Warrington
Wed, 27 September 2023 a

shell energy transition

Shell employees have said they are “deeply concerned” by the oil giant’s shift away from green energy in a blistering open letter to the chief executive.

Wael Sawan, chief executive of Shell, has set out plans to scale back the company’s investment in renewables in a bid to boost profits.

The strategy could involve the FTSE 100 company selling a stake in or even spinning off its global renewable power business entirely. It recently scrapped the role of global head of renewables.

The open letter, which was posted on Shell’s internal website and seen by Reuters, read: “For a long time, it has been Shell’s ambition to be a leader in the energy transition. It is the reason we work here.

“The recent announcements at and after the capital markets day deeply concern us ... We can only hope the optics of the CMD [Capital Markets Day] announcements are deceiving us and that Shell continues its path as a leader in the energy transition.”

The letter, which was addressed to Mr Sawan and Shell’s executive committee, was signed by Lisette de Heiden and Wouter Drinkwaard, two employees in the company’s low-carbon division.

The public rebuke was viewed more than 80,000 times on Shell’s internal website and prompted a string of responses from other employees.

Responding to the letter, Mr Sawan said: “For an organisation at the crux of the energy transition, there are no easy answers and no shortage of dilemmas or challenges. We might not always agree on the way forward, but I feel good about the role Shell is, and will continue, to play.

“I am proud of how we provide affordable and secure energy to people every day, while we work hard to provide lower-carbon solutions to our customers, as we transition over time to a net-zero emissions business.”

Public rebuke of chief executive Wael Sawan's plans was viewed more than 80,000 times on Shell's internal website - REUTERS/Callaghan O'Hare

The internal backlash highlights the dilemma facing Shell as it tries to navigate the shift to renewable energy sources while managing investor demands.

Shares in rival BP, whose chief executive announced his shock resignation earlier this month, have underperformed in recent years as it pumps money into renewables amid surging energy prices in the wake of Russia’s invasion of Ukraine.

Separately on Wednesday, French energy group Total said it will boost fossil fuel production over the next five years in a sharp reversal of its previous policy.

A Shell spokesman denied that the company had changed its strategy, insisting it was still committed to its aim of becoming a net zero emissions business by 2050.

The spokesman added: “We appreciate that our staff are engaged in and have passion for both the energy transition and Shell. That is important and we welcome an open dialogue.

“Shell is playing a meaningful role in addressing the energy transition, and at our recent Capital Markets Day we set out those areas of the energy system of today and tomorrow where we are best placed to invest, compete and win.

“In particular, we have competitive advantages in producing lower-carbon oil, selling LNG [liquified natural gas] that replaces coal, and offering customers low-carbon solutions through EV charging, biofuels and renewable power.”

“Punch-drunk slugnuts” and the language of violence: Tracing the impact of sports slang on modern perceptions of neurodegenerative disease

Peer-Reviewed Publication

UNIVERSITY OF CHICAGO PRESS JOURNALS

Throughout the twentieth century, being “punch drunk” was a commonly encountered condition—one denoted by an equally pervasive term. Similar turns of phrase, like “slugnutty” and “punchy,” persisted for decades in books, newspapers, and magazines. Even today, “punch-drunk,” “goofy,” and “slaphappy” can be found scattered across different media.

This slang originated among working-class populations in the United States and Britain to mock the diminished mental and physical capacity of an individual who had received too many blows to the head. “Punch-drunk slugnuts” exhibited mental decline, grogginess, irritability, and slurred speech.

In “Punch-Drunk Slugnuts: Violence and the Vernacular History of Disease,” published in Isis: A Journal of the History of Science Society, Stephen T. Casper, professor of history at Clarkson University, illustrates how slurs and insults characteristic of a violent interwar culture served as descriptors of debilitating head trauma, and how this language was incorporated into medicine. Casper examines the role slang terms—many associated with the world of contact sports—played in conceptualizing and treating brain injuries and resulting neurological illnesses. Given widespread observation of head trauma and its effects, colloquialisms allowed the illness to be recognizable. At the same time, they inhibited its conceptualization as a serious disease requiring medical intervention.

Casper’s analysis draws on various sources containing vernacular terms to describe damage from repetitive brain injuries, including interviews from the Folklore Project by the Works Progress Administration (WPA), literary descriptions, journalistic pieces, court documents, autobiographical accounts, and medical texts.

Medical professionals studying brain injuries and neurodegenerative disease established connections between their observations and slang circulating in the public sphere. Beginning with Harrison Martland’s essay “Punch Drunk” in 1928, subsequent clinical research included slang terms. Use of this vernacular, in turn, led to the classification of neurological disease induced by repetitive head trauma as “chronic traumatic encephalopathy.” However, the colloquialisms’ myriad connotations allowed for ambiguity in diagnosing the disorder and prevented it from achieving medical legitimacy.

Tracing the history of this vernacular economy reveals a culture that stigmatized sufferers and normalized male violence.

Sports presented a venue where brain injuries were visible, but attempts to medicalize trauma symptoms were challenged. Head trauma was a regular occurrence in high-contact sports, like football and boxing, but the everyday nature of injury was used to downplay its severity. Popular conceptualizations of sports at the time, especially boxing, were predicated on the relationship between masculinity, honor, and violence. Athletes were expected to withstand pain, embody stoicism, and inflict violence as a measure of masculinity. Inability to do so was viewed as a deficiency in one’s manhood. “Punchy” individuals who lost their athletic prowess were objects of derision and fell in social standing. Rather than acknowledge that repeated trauma caused deterioration, society employed racist, classist, and eugenic rationales, casting “punch-drunk slugnuts” as inherently inferior, as subpar fighters, and as dull-witted well before their injuries.

Accepting the affliction as a disease and treating these individuals, Casper argues, would have constituted a critique of mainstream culture and placed blame on its violent practices.

While highlighting the history of impact-related neurodegenerative disease and its lexicon, Casper also elaborates on “a disease population experience that fought against its own discovery” and how tendencies to dismiss the effects of recurrent head trauma continue today. 

“Having originated from culture, been contested by culture, and remade by culture, the disease’s treatment demanded an impossible unmaking of culture. From its rough linguistic and anthropological origins to the uncovering of its biological specificity, the history of this disease traces our chronology of normal violence as entertainment, reveals its legacies in donated brains, and, above all, foretells tragic futures.”

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JOURNAL

Isis

DOI

10.1086/719720 

METHOD OF RESEARCH

Content analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Punch-Drunk Slugnuts: Violence and the Vernacular History of Disease

Stephen T. Casper discloses that he is retained by plaintiffs as an expert witness in medical history in pending concussion litigation involving American football, hockey, soccer, and rugby. He is a member of the Repercussions Group. He receives honoraria for lectures, as well as book royalties from the University of Manchester Press and Rochester University Press.

Why aren’t brain injuries taken seriously?

WWI helmets protect against shock waves

WHAT THEY CALL CONCUSSION OR SERIOUS BRAIN TRAUMA WAS ONCE KNOWN AS SHELL SHOCK AND LAST CENTURY DURING THE BIG ONE WWI IT WAS AN EXECUTABLE OFFENSE ON THE BATTLEFRONT FOR COWARDICE

SEE https://plawiuk.blogspot.com/search?q=WWI

SEE https://plawiuk.blogspot.com/search?q=SHELL+SHOCK

SEE https://plawiuk.blogspot.com/search?q=BATTLE+FATIGUE

Brain Injuries Are Common in Battle. The Military Has No Reliable Test for Them.


Dave Philipps and Thomas Gibbons-Neff

U.S. troops at Ayn al Asad Air Base in western Iraq hunkered down in concrete bunkers last month as Iranian missile strikes rocked the runway, destroying guard towers, hangars and buildings used to fly drones.



© Sergey Ponomarev for The New York Times Ayn al Asad Air Base in western Iraq after an Iranian missile attack on Jan. 8. The number of service members experiencing symptoms associated with brain injuries has since topped 100.

When the dust settled, President Trump and military officials declared that no one had been killed or wounded during the attack. That would soon change.


A week after the blast, Defense Department officials acknowledged that 11 service members had tested positive for traumatic brain injury, or TBI, and had been evacuated to Kuwait and Germany for more screening. Two weeks after the blast, the Pentagon announced that 34 service members were experiencing symptoms associated with brain injuries, and that an additional seven had been evacuated. By the end of January the number of potential brain injuries had climbed to 50. This week it grew to 109.

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The Defense Department says the numbers are driven by an abundance of caution. It noted that 70 percent of those who tested positive for a TBI had since returned to duty. But experts in the brain injury field said the delayed response and confusion were primarily caused by a problem both the military and civilian world have struggled with for more than a decade: There is no reliable way to determine who has a brain injury and who does not.

Top military leaders have for years called traumatic brain injury one of the signature wounds of the wars in Iraq and Afghanistan; at the height of the Iraq war in 2008, they started pouring hundreds of millions of dollars into research on detection and treatment. But the military still has no objective tool for diagnosing brain injury in the field. Instead, medical personnel continue to use a paper questionnaire that relies on answers from patients — patients who may have reasons to hide or exaggerate symptoms, or who may be too shaken to answer questions accurately.

The military has long struggled with how to address so-called invisible war wounds, including traumatic brain injury and post-traumatic stress disorder. Despite big investments in research that have yielded advances in the laboratory, troops on the ground are still being assessed with the same blunt tools that have been in use for generations.

The problem is not unique to the military. Civilian doctors struggle to accurately assess brain injuries, and still rely on a process that grades the severity of a head injury in part by asking patients a series of questions: Did they black out? Do they have memory problems or dizziness? Are they experiencing irritability or difficulty concentrating?

“It’s bad, bad, bad. You would never diagnose a heart attack or even a broken bone that way,” said Dr. Jeff Bazarian a professor of emergency medicine at the University of Rochester Medical Center. “And yet we are doing it for an injury to the most complex organ in the body. Here’s how crazy it gets: You are relying on people to report what happened. But the part of the brain most often affected by a traumatic brain injury is memory. We get a lot of false positives and false negatives.”

Without a good diagnosis, he said, doctors often don’t know whether a patient has a minor concussion that might require a day’s rest, or a life-threatening brain bleed, let alone potential long-term effects like depression and personality disorder.

At Ayn al Asad, personnel used the same paper questionnaires that field medics used in remote infantry platoons in 2010. Aaron Hepps, who was a Navy corpsman in a Marines infantry company in Afghanistan at that time, said it did not work well then for lesser cases, and the injuries of many Marines may have been missed. During and after his deployment, he counted brain injuries in roughly 350 Marines — about a third of the battalion.

After the January missile attack, Maj. Robert Hales, one of the top medical providers at the air base, said that the initial tests were “a good start,” but that it took numerous screenings and awareness among the troops to realize that repeated exposure to blast waves during the hourlong missile strikes had affected dozens.

Traumatic brain injuries are among the most common injuries of the wars in Iraq and Afghanistan, in part because armor to protect from bullet and shrapnel wounds has gotten better, but they offer little protection from the shock waves of explosions. More than 350,000 brain injuries have been reported in the military since 2001.

The concrete bunkers scattered around bases like Ain al Assad protect from flying shrapnel and debris, but the small quarters can amplify shock waves and lead to head trauma.

The blasts on Jan. 8, one military official said, were hundreds of times more powerful than the rocket and mortar attacks regularly aimed at U.S. bases, causing at least one concrete wall to collapse atop a bunker with people inside.

Capt. Geoff Hansen was in a Humvee at Ayn al Asad when the first missile hit, blowing open a door. Then a second missile hit.

“That kind of blew me back in,” he said. “Blew debris in my face so I went and sat back down a little confused.”

A tangle of factors make diagnosing head injuries in the military particularly tricky, experts say. Some troops try to hide symptoms so they can stay on duty, or avoid being perceived as weak. Others may play up or even invent symptoms that can make them eligible for the Purple Heart medal or valuable veteran’s education and medical benefits.

And sometimes commanders suspect troops with legitimate injuries of malingering and force them to return to duty. Pentagon officials said privately this week that some of the injuries from the Jan. 8 incident had probably been exaggerated. Mr. Trump seemed to dismiss the injuries at a news conference in Davos, Switzerland, last month. “I heard they had headaches,” he said. “I don’t consider them very serious injuries relative to other injuries I have seen.”

In the early years of the war in Iraq, troops with concussions were often given little medical treatment and were not eligible for the Purple Heart. It was only after clearly wounded troops began complaining of poor treatment that Congress got involved and military leaders began pressing for better diagnostic technology.

Damir Janigro, who directed cerebrovascular research at the Cleveland Clinic for more than a decade, said relying on the questionnaire makes accurate diagnosing extremely difficult.

“You have the problem of the cheaters, and the problem of the ones who don’t want to be counted,” he said. “But you have a third problem, which is that even if people are being completely honest, you still don’t know who is really injured.”

In civilian emergency rooms, the uncertainty leads doctors to approve unnecessary CT scans, which can detect bleeding and other damage to the brain, but are expensive and expose patients to radiation. At the same time doctors miss other patients who may need care. In a war zone, bad calls can endanger lives, as troops are either needlessly airlifted or kept in the field when they cannot think straight.

Mr. Janigro is at work on a possible solution. He and his team have developed a test that uses proteins found in a patient’s saliva to diagnose brain injuries. Other groups are developing a blood test.

Both tests work on a similar principle. When the brain is hit by a blast wave or a blow to the head, brain cells are stretched and damaged. Those cells then dispose of the damaged parts, which are composed of distinctive proteins. Abnormal levels of those proteins are dumped into the bloodstream, where for several hours they can be detected in both the blood and saliva. Both tests, and another test being developed that measures electrical activity in the brain, were funded in part by federal grants, and have shown strong results in clinical trials. Researchers say they could be approved for use by the F.D.A. in the next few years.

The saliva test being developed by Mr. Janigro will look a bit like an over-the-counter pregnancy test. Patients with suspected brain injuries would put sensors in their mouths, and within minutes get a message that says that their brain protein levels are normal, or that they should see a doctor.

But the new generation of testing tools may fall short, said Dr. Gerald Grant, a professor of neurosurgery at Stanford University and a former Air Force lieutenant colonel who frequently treated head injuries while deployed to Iraq in 2005.

Even sophisticated devices had trouble picking up injuries from roadside bombs, he said.

“You’d get kids coming in with blast injuries,” he said, “and they clearly had symptoms, but the CT scans would be negative.”

He was part of an earlier effort to find a definitive blood test, which he said in an interview was “the holy grail.” But progress was slow. The grail was never found, he said, and the tests currently being developed are helpful for triaging cases, but too vague to be revolutionary.

“Battlefield injuries are complex,” he said. “We still haven’t found the magic biomarker.”

Why aren’t brain injuries taken seriously?

WWI helmets protect against shock waves

WHAT THEY CALL CONCUSSION OR SERIOUS BRAIN TRAUMA WAS ONCE KNOWN AS SHELL SHOCK AND LAST CENTURY DURING THE BIG ONE WWI IT WAS AN EXECUTABLE OFFENSE ON THE BATTLEFRONT FOR COWARDICE

SEE https://plawiuk.blogspot.com/search?q=WWI

SEE https://plawiuk.blogspot.com/search?q=SHELL+SHOCK

SEE https://plawiuk.blogspot.com/search?q=BATTLE+FATIGUE

South Africa court suspends Shell seismic survey plan
AFP 

A South African court on Tuesday blocked Shell from using seismic waves to explore for oil and gas in the Indian Ocean, in a victory for environmentalists worried about the impact on whales and other species.

© RODGER BOSCH The ruling is a temporary victory for green groups who said seismic exploration would harm whales, seals and other fragile species

Backing a suit filed by conservationists, the High Court in the Eastern Cape town of Makhanda ruled that Shell was "hereby interdicted from undertaking seismic survey operations."

The fossil fuel giant had announced plans to start exploration over more than 6,000 square kilometres (2,300 square miles) of ocean off South Africa's Wild Coast region.

The Wild Coast is a 300-kilometre (185-mile) stretch of natural beauty, dotted with marine and nature reserves.

The area of interest lies 20 kilometres (12 miles) off the coast, in waters 700 to 3,000 meters deep (2,300 to 10,000 feet).

Shell's scheme entails using seismic shockwaves which bounce off the sea bed, and whose signature can point to potentially energy-bearing sites.

"Many sea creatures will be affected, from whales, dolphins, seals, penguins to tiny plankton that will be blasted," said Janet Solomon, of the environmental group Oceans Not Oil in the runup to the hearing.

Exploration had been scheduled to start on December 1 and last up to five months.

A Shell spokesperson said Tuesday: "We respect the court's decision and have paused the survey while we review the judgement.

- 'Huge victory' -

"Surveys of this nature have been conducted for over 50 years with more than 15 years of extensive peer-reviewed scientific research."

The campaigners were jubilant at the ruling, but stressed that the relief was only temporary.

"It's a huge victory," said Katherine Robinson of the NGO Natural Justice.

"But the struggle is not over -- this decision is just the interdict. We understand that the proceedings will continue."

A petition against the project had gathered nearly 85,000 signatures.

Campaigners said the scheme would entail "one extremely loud shock wave every 10 seconds, 24 hours a day, for five months at a time."

Shell argued that it took "great care to prevent or minimise" the impact on wildlife, and promised that the work would strictly follow the guidelines of the Joint Nature Conservation Committee, a UK government adviser on nature conservation.

On Tuesday, it also stressed what it described as the benefits for South Africa if oil and gas were found.

"South Africa is highly reliant on energy imports for many of its energy needs," the company's spokesperson said.

"If viable resources were to be found offshore, this could significantly contribute to the country’s energy security and the government’s economic development programmes."

South Africa's energy ministry had backed the scheme, and lashed those who opposed it as thwarting investment in the country's development.

The High Court's ruling comes after a lower court rejected the conservationists' suit in early December.

Several fishermen and local groups were also part of the petition.

cld-ger/ri/lc

AUSTRALIAN SCIENTISTS HELP CATCH THE FIRST MOMENTS OF A SUPERNOVA

• #Science
• #Astrophysics
• #EM Spectrum
• #Stars
• #Supernovae

WRITTEN BY RAMI MANDOW

Astronomers from the Australian National University, have led an international team of researchers to observe, for the first time, the early light curve from a supernova event and modelled the type of progenitor star that caused it.

The initial shock breakout of light just as the supernova occurs on a star. Credit: NASA.

Astronomers from the Australian National University (ANU) have led an international team of researchers to make the first observations of the light emitted just as a supernova explosion detonates in space. The data has also provided an opportunity to test different models in which the progenitor star can be inferred through measuring the supernova’s light curve.

Until now, most of the light received from supernovae events was the result of astronomers making detections after the initial blast and produced by the decay of radioactive elements in the expanding debris shell from the blast, which usually occurs sometime after the original event.

But this new research, published in the journal Monthly Notices of the Royal Astronomical Society, outlines the detection of a light curve peak (known as a ‘shock cooling light-curve’)  which presents the burst of emissions immediately after the explosion occurs – a rare observation, as these events fade quickly. The new discovery has been named SN2017jgh.

"This is the first time anyone has had such a detailed look at a complete shock cooling curve in any supernova," said PhD scholar and lead author, Mr Patrick Armstrong.

"Because the initial stage of a supernova happens so quickly, it is very hard for most telescopes to record this phenomenon.”

"Until now, the data we had was incomplete and only included the dimming of the shock cooling curve and the subsequent explosion, but never the bright burst of light at the very start of the supernova.

"This major discovery will give us the data we need to identify other stars that became supernovae, even after they have exploded," he said.

Supernovae events can be triggered by a number of different factors, including merging compact stars like white dwarfs or the collapse of more massive stars. So violent and powerful are these events, that they forge a large number of elements that we see around us including many of the heavier elements in the periodic table.

By studying the lights from these events, effectively astronomers are given a tool to delve into the formation of elements across the Universe. Additionally, by studying the shock cooling light-curves that is produced during supernovae, astronomers can now also start to answer some of the ongoing questions around the dynamics of collapsing stellar objects once they reach the end of their main sequence lives.

THE STAR THAT WAS…

Artist illustration of a yellow supergiant star. Credit: M. Jadraef.

Based on the observations made of the shock cooling light-curves, and modelling completed, the research team were able to determine that the progenitor star to SN2017jgh was a yellow supergiant star. These types of stars are usually evolved F or G class stars that are no longer burning hydrogen in their cores, so have since expanded to enormous sizes – which in turn increases their luminosity.

Yellow supergiants usually have a temperature range of around 4,000 – 7,000 Kelvin, with their luminosities shining from about 1,000 times that of our Sun, but in the most extreme cases, this can also get up to 100,000 times the solar luminosity.

SN2017jgh progenitor star was also identified in imagery, prior to the explosion, and determined to have had an effective temperature somewhere between 4000 – 5000 Kelvin and contain an original mass of 17 times that of our Sun.

However, yellow supergiants are less common than the regular red supergiants that are dominant in the night sky, like Antares and Betelgeuse, and are usually smaller in size. The northern pole star, Polaris, is catalogued as a yellow supergiant.

SN2017jgh also features a surrounding envelope of hydrogen gas whose mass is expected to be ranged between 0.5 - 1.7 times that of the Sun. These envelopes form as the star ages and throw off enormous volumes of hydrogen into their local surrounding regions through expected mechanisms like strong stellar winds, stellar rotation, binary interactions and nuclear instabilities.

The size of the hydrogen envelope from SN2017jgh is reported in the paper to have a radius of approximately 130 solar radii, which equates to about 180 million kilometres – so if you placed it where our Sun was, its surface would lie beyond the Earth’s orbit. 

The supernovae event was located 0.157 arcseconds away from its host galaxy centre, which resides at a distance of just over one billion light-years from Earth.

SUPERNOVAE IN A RANGE OF FLAVOURS

Classifying supernovae events into categories, based on how they exhibit hydrogen, silicon and helium features. Credit: H. Stevance.

Supernovae can be triggered by a number of different progenitor objects and events. The taxonomy of these events is divided into two main classes – those that feature hydrogen in the light curve’s spectrum, and those that don’t. From these two classes, further sub-classes are also established.

The first type, Type I supernovae, is considered thermal runaway events, and usually associated with massive compact objects like white dwarfs. These supernovae are usually triggered when accretion of material builds up on one star from a companion; an accretion of materials create enough pressure to trigger a core ignition, or when two compact objects merge (though in the case of Neutron Star mergers, these are known as a Kilonova).

But the other category, called Type II supernovae, is a much more powerful and destructive event. These are triggered when a massive star (usually 8 – 25 solar masses) can no longer produce core energy to sustain the outwards pushing radiation pressure and thus succumbs to the inward gravitational force.

This causes the star to collapse inwards, crushing the core before rebounding in the supernova explosion – this is also how exotic objects like neutron stars, pulsars and black holes are born.

Type II Supernovae can be further sub-categorised depending again on a number of different factors presented in the light curve observed (esp. if it does or doesn’t feature silicon, helium, narrow lines, or an evolving spectrum).

One indicator that the progenitor star had a large hydrogen envelope surrounding it is the fading of hydrogen lines weeks after the initial explosion, giving way to the rise of dominant helium lines, suggesting that a lot of the hydrogen layer of the star had become stripped during the envelope shedding.

READING THE LIGHT CURVE OF AN EXPLODING STAR

When it comes to the Type II supernovae (core-collapse models), there are generally two prominent peaks that appear in the light curve signature. The first is created when photons that have been trapped inside the star rush outwards in the early onset of the violent explosion, and only last a few days. These emissions can provide astronomers with lots of information about the progenitor star, and the shockwave generated from the explosion.

The second, are caused by the nuclear-powered emissions from the radioactive decay of 56Ni into cobalt, then iron over the course of some time, usually coming in a few days and weeks after the event. This is the source of the second peak in the light curve, but also eventually reduces in luminosity over the period. It is during these times in which new elements are forged through nucleosynthesis associated with the stellar explosion.

Historically, a number of shock cooling light-curves have been observed as reported for other supernovae events, but these new findings have allowed astronomers to capture the complete evolution of the initial peak associated with a supernova for the first time.

Whilst many supernovae occur and can be studied, catching them in their early onset is the only time where these shock cooling light-curves can be observed, and so having telescopes pointed at the right place and the right time is a rare chance.

Infographic on what the different light curves of supernovae look like - note the difference in the shape of the curves, as well as the elementary composition. The two main categories of supernovae events can be classed under thermonuclear and core-collapse models. Credit: H. Stevance.

ANALYSIS AND MODELLING OF THE LIGHT FROM 2017JGH

The Kepler Space Telescope, which assisted in obtaining data from this discovery. Credit: NASA.

A number of different observations were made to come to establish the results outlined in this latest paper, relating to SN2017jgh. Originally, the supernova was discovered by Pan-STARRS1 – a 1.8-metre telescope located in Maui, Hawaii. Using the 1.4 Gigapixel camera, it identified the supernova which presented at roughly magnitude 20.

Photometry (measuring light in different bands in similar wavelengths that the humane eye observes in) was also produced using Pan-STARRS1 filtering system (grizy), and the Swope Supernova Survey (SSS) – which uses a 1-metre aperture telescope, located in Las Campanas in Chile also complemented with its own observations. The SSS telescope’s filtering system (gri) observed the supernova between December 2017 and February 2018.

As well as ground-based observations, the Kepler/K2 spacecraft took observations of the event from orbit, avoiding any disturbances produced by our atmosphere. It observed the event at 30 minutes cadence over an 80-day campaign, which really highlighted the rise in the light curve’s first peak in lots of detail.

For the optical spectroscopy component, the Gemini Multi-Object Spectrograph on the Gemini South Telescope (also located in Chile) was used and took in observations of the spectrum in early January 2018, two days prior to the radioactive maximum peak which occurs roughly 14 days after discovery.

Overall, the light curves that were analysed across all observations point to a similar supernova to another observed in the early 1990s, known as SN1993J, which also featured a yellow supergiant star.

A number of shock cooling light-curve models were then used to test the results, with the SW 17 model fitting the most accurate to the data observed.

"We've proven one model works better than the rest at identifying different supernovae stars and there is no longer a need to test multiple other models, which has traditionally been the case," said Astrophysicist and ANU researcher Dr Brad Tucker, also a co-author of the paper.

"Astronomers across the world will be able to use SW 17 and be confident it is the best model to identify stars that turn into supernovas."

As well as providing global researchers with a well-fitted model for these early peaks in supernovae events, these new findings now showcase a little bit more of the detail around those first, early moments during one of the most violent and destructive incidents in our Universe, which in turn gives birth to new materials.

"This will provide us with further opportunities to improve our models and build our understanding of supernovae and where the elements that make up the world around us come from," said Mr Armstrong.

Why aren’t brain injuries taken seriously?

Mike Bebernes Editor, Yahoo News 360•February 11, 2020
“The 360” shows you diverse perspectives on the day’s top stories and debates

What’s happening

More than 100 members of the U.S. military suffered traumatic brain injuries as a result of an Iranian missile attack on a base in Iraq that housed American troops, according to the U.S. Department of Defense.

Iran bombarded the base in early January in retaliation for an American airstrike that killed Qassem Soleimani, one of the country’s top generals. Though there were no U.S. fatalities, the number of military members who have been treated for brain injuries has gradually increased in the weeks since the attack. Last month, President Trump downplayed the injuries, saying the soldiers were experiencing “headaches,” which he didn’t consider “very serious injuries relative to other injuries.”

To the general public, traumatic brain injury (TBI) is most commonly understood to be caused by a direct blow to the head like the ones football players endure. The impact from an explosion — even if it doesn’t cause bodily injury — could cause TBI. Brain injuries have been called the “signature wound” of the wars in Afghanistan and Iraq, where improvised explosive devices have been a persistent threat. More than 413,000 American soldiers have suffered TBI since 2000, according to the Department of Defense.

Most of those cases involved mild TBI, which can lead to headaches, cognitive impairment, mood changes and fatigue in the short term. Research has shown that even mild brain injuries can be linked to a increased long-term risk of depression, post-traumatic stress disorder and suicide.

Why there’s debate

The president’s comments echo a view, prevalent in the military and in sports, that brain injuries aren’t considered as serious as physical injuries. Part of the disconnect may stem from the nature of the injuries. A bullet wound, for example, is immediately noticeable and easily understood as life-threatening. The symptoms of head injuries, however, can take days to show up and are often difficult to define. Severe outcomes, like depression, may not manifest for months or even years and can be difficult to attribute directly to head trauma.

Some military veterans say the culture of the armed forces puts pressure on soldiers to return to action unless physically unable, which can lead to TBI symptoms going unreported. Others argue that military leadership has been too slow to respond to the issue and that the government doesn’t do enough to provide mental health services to veterans after their service is complete.

What’s next

The modern understanding of the impact of traumatic brain injuries is still relatively new. Scientists and doctors are working to develop better methods to diagnose, monitor and treat TBI. The military has instituted new procedures for managing brain injuries within its ranks in recent years. President Trump, however, appears committed to his view that TBI isn’t as serious as other injuries. “I viewed it a little bit differently than most, and I won't be changing my mind on that," he said Monday.
Perspectives

Symptoms can take time to surface

“The long-lasting effects of TBI can be delayed, and its victims can appear unchanged to the eye. Because of this, it is easy to dismiss mild TBI or concussion as a bump to the head, and the victims of TBI are often returned back to the field, the court, work or the battlefield all too soon without the necessary neuropsychological testing and subsequent treatment.”
— Neurologist Starane Shepherd, Newsweek

Veterans often see their symptoms as personality problems

“Victims of traumatic brain injury often blame themselves for their changed behavior, not realizing that blows or force to the head have caused lasting harm. … Step one is helping them understand they have injuries, not character flaws.” — Dr. Chrisanne Gordon, Columbus Dispatch

Fear of judgment prevents soldiers from seeking treatment

“A major hurdle has been to destigmatize brain injury and make people realize that injuries to the brain that can’t be seen are just as serious — and sometimes more difficult to treat — than bloody wounds to other parts of the body.” — Editorial, Washington Post

Mental health is consistently treated as less seriously than physical health

“Historically, mental health services get shortchanged in funding and support across the country, but the failure to care for the war fighters has been notably shameful. Looking back 18 years, we find that the medical campaign to treat psychological problems and brain injury has largely failed.” — Stephen N. Xenakis, USA Today

Medical science is only starting to understand brain injuries

“It's the brain — and medicine is only on the forefront of understanding what, exactly, goes on in there.” — Leah Asmelash, CNN

Many doctors still rely on ineffective treatments

"A lot of physicians will say, 'Well, you shouldn't do anything. Go into a dark room, don't strain the brain and wait until you recover.’ … And we have a national epidemic of people that are sitting in a room waiting for their headache to go away.” — Dr. Jamshid Ghajar to Military.com

TBI symptoms are often discounted

“What I know is that if you show most people an invisible wound, you’ll get invisible compassion. Wear earplugs all the time, and even your close friends will just blow it off. … Empathy requires stimulus, and in the average person’s perspective, anybody can just ‘fake’ post-traumatic stress or a TBI.” — Military veteran Bryan Box, New Republic

Brain Injuries Are Common in Battle. The Military Has No Reliable Test for Them.

WHAT THEY CALL CONCUSSION OR SERIOUS BRAIN TRAUMA WAS ONCE KNOWN AS SHELL SHOCK AND LAST CENTURY DURING THE BIG ONE WWI IT WAS AN EXECUTABLE OFFENSE ON THE BATTLEFRONT FOR COWARDICE

SEE  https://plawiuk.blogspot.com/search?q=WWI

SEE  https://plawiuk.blogspot.com/search?q=SHELL+SHOCK

SEE  https://plawiuk.blogspot.com/search?q=BATTLE+FATIGUE