Monday, September 28, 2026

 

The eruption that destroyed Pompeii is helping scientists date Earth's history



Historical accounts of the eruption allow anew recalibration of one of the most versatile dating methods



University of California - Berkeley

Pompeii and Vesuvius

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Mt. Vesuvius towering above the ruins of Pompeii. The volcano's eruption in 79 C.E. inundated the town. Historical accounts of the disaster have now allowed scientists to recalibrate one of the most versatile dating methods, argon-argon dating.

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Credit: By Qfl247, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=14711995






When Pliny the Younger recorded his first-hand experience of the explosion of Mt. Vesuvius 2,000 years ago — a cataclysm that buried Pompeii and killed his uncle, Pliny the Elder — he provided enough detail about the precise date to allow scientists to benchmark methods for dating volcanic eruptions.

In a study to be published this week in the journal Science Advances, scientists from the Berkeley Geochronology Center, UC Berkeley and the University of Padua in Italy report that argon-argon dating calibrated with the inferred date of the eruption — Aug. 24, 79 CE — is now significantly more precise, making it one of the most versatile dating methods available.

The improvement will allow geologists, paleontologists and archaeologists to attach more accurate dates to geologic events of the past, including past eruptions of volcanoes that still threaten dense urban areas like Mexico City, Naples and Yogyakarta in Indonesia. It will also help ground-truth other dating methods, such as carbon-14 dating of organic material and uranium-lead dating of billion-year-old rocks from the early days of planet Earth.

“If you want to put together the eruptive history of a volcano in relatively recent time, precision and accuracy really count,” said study leader Paul Renne, a Berkeley professor in residence of earth and planetary science and director of the independent Berkeley Geochronology Center. “The study shows that you can achieve that kind of highly useful precision and accuracy into the historical realm.”

Accuracy refers to whether a result is correct, whereas precision is a measure of how reproducible the result is. The recalibrated argon-argon dating method, used on eight samples of a potassium-containing volcanic mineral from Vesuvius called sanidine, pegged the eruption at 1,938 ±13 years prior to when the minerals were analyzed in 2025. The actual age of the volcanic minerals was 1,946 years, according to analysis of Pliny the Younger’s writings. The estimate is equivalent to a precision of 0.7% and an accuracy of 0.4%.

“This lets us more precisely infer causality between events in the geologic record, for example a meteor impact structure and a mass extinction,” Renne said. A decade ago, Renne used argon-argon dating to provide precise dates for a meteor impact, volcanic eruptions in India and the dinosaur extinction — all of which took place within a few tens of thousands of years 66 million years ago. These precise dates bolstered the idea that the impact triggered intensified volcanism, providing a one-two punch that led to the extinction of all non-avian dinosaurs.

Thanks to a deep dive into the recorded history of Vesuvius’ eruption by graduate student Caroline Hasler, the team was also able to validate the eruption date attributed to Pliny the Younger — August 24 — to within two months. This enabled the team to more precisely measure the half-life of the decay of potassium-40 to argon-40 that provides the basis for argon-argon dating. That half-life is now 12.044 billion years, give or take 0.088 billion — twice as precise as the previous value determined from nuclear physics.

Pumice from Oplontis

Renne and his team had previously analyzed sanidine from pumice ejected during the 79 CE eruption to ground-truth argon-argon dating. Based on that 1997 analysis, they predicted that they could do better, getting the precision down to less than 1%. He and his team have now achieved that goal, thanks to better pumice samples, an improved mass spectrometer and updated neutron irradiation techniques.

Argon-argon dating relies on the natural decay of potassium-40 in volcanic rock to argon-40, which is not normally present in minerals prior to eruption. Scientists irradiate rocks with neutrons to turn a non-radioactive isotope of potassium, potassium-39, into argon-39, and then compare the relative amounts of the two argon isotopes. The more argon-40 relative to argon-39, the older the sample.

In 1998, co-author Andrea Marzoli of the University of Padua obtained new, more potassium-rich pumice samples from Oplontis, another Roman town buried in ash. Unlike previous samples, the new ones came from the earliest stage of the Vesuvius eruption. Magma chambers under stratovolcanoes like Vesuvius tend to stratify, with iron and magnesium concentrating at the bottom of the chamber while soluble elements like potassium remain at the top. As a result, potassium-rich magma comes out first and ends up at the bottom of ash and pumice deposits. Marzoli’s pumice came from these bottom deposits.

Those samples were shelved and never analyzed, but several years ago, graduate students Hasler, Anthony Fuentes and Andy Tholt led by postdoctoral fellow Jack Carter in Renne’s lab suggested pulling out Marzoli’s 30-year-old samples and trying to improve on the 1997 results. The team had previously published a reconciliation of the two dating methods most commonly used for rocks — argon-argon and uranium-lead — and precisely calibrating argon-argon dating was a key component of that work.

“They came up with a Bayesian scheme — published in 2025 — to intercalibrate these two most important geochronometers that we have, which have not been giving us consistent results over the years,” Renne said. The Vesuvius results from 1997 were included in this intercalibration, but were not precise enough to have much weight in the result. The new results change that.

“It was really just a combination of better samples, instrumental advantage and a more concerted effort. All of those things came together,” Renne added. He credits co-author Bill Cassata with a major role in developing the analytical strategy and data analysis.

Before they could begin, however, Hasler had to resolve inconsistencies in the historical record. Some historians think the eruption took place later in the fall of 79 CE, based on a coin found at Pompeii that they say could only have been stamped in September. Hasler compared the coin with other contemporary Roman coins and concluded that it was likely made before September. Adopting a liberal two-month uncertainty in the timeline turned out not to be important in calibrating the dating technique, but was key in establishing the half-life of potassium-40.

Renne said that more accurate and precise argon-argon dating will be invaluable in calibrating radiocarbon dating, which is the dominant method of attaching dates to materials such as wood that are younger than about 55,000 years.

“We're hoping to really unify as many geologic dating methods as we can by using the same mathematics, the same Bayesian approach, and just bringing more data, more raw observations into that mix,” he said. “But argon-argon dating is always going to be a standard — it's going to be an important calibrant in that sense.”

Besides contributing to the calibration of the argon/argon dating method, he said, the study establishes a new benchmark for the ability of the method to date very recent eruptions with decadal accuracy.

The work was funded by the National Science Foundation (2102788, 2030393), the Ann and Gordon Getty Foundation and the Berkeley Geochronology Center.

SPACE/COSMOS

Great news from Saturn’s moon Enceladus in the search for life in space




Freie Universitat Berlin






What are the chances of finding extraterrestrial life in our solar system? Professor Frank Postberg, planetary scientist at Freie Universität Berlin, has just published a study in Science Advances with a team of international researchers, in which they present new evidence that it is easier to determine the constituents of the ocean hidden under Enceladus’s icy surface than previously assumed. Postberg was also part of a second study published on the same day, in which he and another planetary scientist from Freie Universität, Dr. Nozair Khawaja, contributed to research that reveals that certain microorganisms could actually tolerate the conditions in Enceladus’s ocean better than was previously thought. These results increase the probability of finding evidence of life on Saturn’s moon.

What Makes Enceladus so Attractive in the Search for Life in Space?

Enceladus is considered to be one of the most promising places to search for extraterrestrial life in our solar system. Researchers suspect that under the moon’s icy crust there is a global ocean of liquid water and a rocky core further below. Due to cryovolcanic activity, gigantic plumes break through cracks in the crust at the moon’s south pole, ejecting ice particles hundreds of kilometers into space.

NASA’s Cassini spacecraft passed through these plumes multiple times to analyze its composition. Enceladus’s ocean is the only extraterrestrial “body of water” from which scientists have been able to directly analyze samples. The samples revealed traces of various salts and organic compounds. Furthermore, previous analyses conducted by Cassini gave indications of hydrothermal processes on the seafloor and other conditions that are significant in supporting life.

Enceladus Ice Plumes Separate and Sort the Ocean’s Components

Postberg’s study, “Cassini CDA Observes Compositional Segregation of Enceladus’ Ice Grains from Slow Freezing and Fragmentation of Oceanic Spray,” includes surprising findings about what happens to the ocean water on its way into space. The international team of scientists working on the study used Cassini data, long-term laboratory experiments, and theoretical models to reconstruct the process.

Droplets form at the ocean’s surface as bubbles filled with gas float up and pop. Water vapor then carries the droplets through cracks in the ice shell out into space. Until now, scientists believed that they froze instantaneously, however these new findings reveal that they freeze slowly. Due to this slow process, most components (including dissolved ones) separate from each other. Salts and organic materials are thus distributed at different locations inside each freezing droplet. Various types of previously dissolved salts also get segregated in the process; for example, sodium chloride (table salt) separates from sodium carbonate.

On their way up, the frozen droplets are accelerated to speeds of up to 1,000 km/h. If they smash into the walls of the icy cracks, they break into fragments only a few micrometers in size before they shoot into space. This results in the ice particles often consisting of just one highly concentrated, previously segregated, substance.

“Enceladus actually does a lot of the work for us in preparing samples for analysis that usually take a lot of effort in chemical labs on Earth,” says Postberg, who led the study. “The oceanic constituents are separated from each other and simultaneously concentrated into individual ice particles.”

Making It Easier to Find Signs of Life

When probing Enceladus’s plumes, this mechanism is not just helpful in characterizing the ocean as a potential habitat for life, it is also particularly interesting in the search for biosignatures, i.e., measurable indications of life. If one of these ocean droplets contained components from alien microbes, they could be segregated from other components in the freezing process. After fragmentation, the microbial material would potentially only be contained in a small fraction of ice particles; however, in those ice particles it would be found in high concentration and in relatively pure form.

“That is great news in the search for life,” says Postberg. “Future spacecrafts will have to analyze many individual ice particles in the plume. But if they come across one with microbial material in it, they could identify biosignatures in the particle relatively easy with already available technology.”

This discovery could have important implications for future space missions to Enceladus, such as the ESA’s L4 mission, which is currently in planning. The mission will be specifically looking for signs of life on Saturn’s moon. Postberg’s lab at Freie Universität Berlin has previously conducted laboratory studies that demonstrated the capacity for specialized instruments to detect microbial cellular material in individual particles from the ice plumes.

Could Life Really Exist on Enceladus?

A recent study is also providing new insights into this question. On the same day Postberg’s article appeared in Science Advances, another article in the same journal was published by scientists at Ludwig-Maximilians-Universität München (LMU): “Enceladus-Like Geochemistry Fuels Methanogenesis under Extreme CO₂-Limitation.” Postberg and another colleague from Freie Universität Berlin, Dr. Nozair Khawaja, contributed to this study. In it, scientists were able to reproduce the conditions of Enceladus’s ocean in a laboratory. The ocean has a very low concentration of oxygen, a very high concentration of carbonate, and is very alkaline (with pH values of 10 or 11). After recreating these conditions, including its hydrothermal interaction with the rocky ocean floor, they introduced Methanothermococcus okinawensis into the contained environment. This microorganism is a methane-producing archaean that normally lives near deep-sea hydrothermal vents on Earth. They do not need oxygen, which is rare on Enceladus, to survive. Instead their metabolism requires only hydrogen and carbon dioxide.

The results were surprising: The organism failed to grow in an optimum laboratory medium at such a high pH, lacking dissolved carbon dioxide. By contrast, in the Enceladus simulant it continued to grow, producing methane using hydrogen generated by water-rock reactions. Under the simulated Enceladus conditions, the microorganisms were even able to adapt their metabolism to the low amounts of carbon dioxide. “This was really a surprise to us,” Khawaja said. “This was an experiment for which we did not expect such a successful outcome.”

Taken together, the two studies in Science Advances shed new light on the search for extraterrestrial life. “On Enceladus the specific geochemical conditions might allow one of the oldest known metabolic systems on Earth to work, even in very alkaline environments,” Postberg says.  “While that doesn’t mean that there is life on Saturn’s moon, our first study shows that – in the event that there is – future space missions might have a good chance of finding traces if they analyze individual ice grains from Enceladus’s plume.”

Freie Universität Researchers Investigating the Emergence of Life in Space

What are the prerequisites for planets and moons to provide suitable conditions for the formation and preservation of life? This is a central research topic for planetary scientists at Freie Universität Berlin. A new Collaborative Research Center funded by the German Research Foundation (DFG), CRC1759 “Habitability as a Fundamental Planetary Process,” was launched in July 2026. The research center is led by Professor Lena Noack with Professor Frank Postberg as her deputy, both of whom are planetary scientists at Freie Universität Berlin. The research center will study the processes that could have enabled life to emerge in space in the first place, on Enceladus and other celestial bodies, both in our solar system and beyond.

 

New study detects ammonia and unexpected chill on a distant giant planet


A UMD-led team found water, methane and a rare ammonia signal in the atmosphere of HATS-6 b, a large planet orbiting a tiny star—raising new questions about how giant planets form




University of Maryland






Using the James Webb Space Telescope (JWST), a team of astronomers led by the University of Maryland identified water, methane and ammonia in the atmosphere of HATS-6 b, a giant planet 500 light-years away from Earth. Observations captured by JWST also revealed that HATS-6 b may be significantly cooler than expected compared to standard calculations of its temperature—suggesting that the planet’s relationship with its star may be far more complicated than previously thought. 

The team’s findings published in the Astronomical Journal on September 8, 2026, raise new questions about how giant planets form and evolve.

HATS-6 b is roughly the size of Jupiter, completing an orbit every three days around an M dwarf—a small, cool, reddish star. Planets are built from the leftover disk of gas and dust that surrounds such stars after their formation, and a smaller star leaves behind only small disks. But HATS-6 b’s gigantic size doesn’t quite fit into that rule, considering how small the star it orbits is.

“These smaller stars don’t have enough material or enough time to create planets as big as Jupiter and as big as Saturn,” explained the study’s lead author Giannina Guzmán Caloca, an astronomy Ph.D. candidate at UMD. “So, the fact that HATS-6 b can exist is really interesting because it shouldn’t be possible with what we know.”

Astronomers know only about 40 such planets. HATS-6 b is one of seven being studied in a JWST program called Giant Exoplanets around M-dwarf Stars (GEMS). The program is designed to compare these outliers against the better-understood giants circling stars like our sun. 

“Every one of these planets is a challenge to formation theory,” Guzmán Caloca said. “By measuring what their atmospheres are made of, we can start to ask whether they were built the same way as the hot Jupiters around sun-like stars or whether something different is going on.”

Using a technique called transmission spectroscopy, which involves watching starlight filter through a planet’s atmosphere, the team identified four molecules in HATS-6 b’s air: water, methane, ammonia and carbon dioxide. The discovery marks only the second time the technique detected ammonia on a distant world. 

“Carbon, hydrogen and oxygen are all things that have been previously found in atmospheres of giant planets outside our solar system, but ammonia is something almost never detected before,” Guzmán Caloca explained. “It’s an entirely new molecule to think about.”

Because nitrogen-bearing molecules like ammonia should be more abundant in cooler giant planets than in scorching hot Jupiter-like ones, the discovery supports the theory that planets that orbit M-dwarf stars may be a chemically distinct population.

HATS-6 b's unexpected temperature raises another major question. The commonly cited temperature for HATS-6 b—near 800 degrees Fahrenheit—is not an exact measurement but a calculation that assumes the planet absorbs all the light its star delivers and spreads that heat evenly. But scientists’ early analyses returned temperatures closer to 250 degrees Fahrenheit, a figure that’s physically improbable for a planet orbiting its star every three days. 

“If the planet is genuinely that cool, it means that something is probably reflecting a great deal of starlight back into space before it can warm anything,” Guzmán Caloca explained. “The likeliest explanation is cloud and haze wrapping the planet the way they wrap Venus.”

The team’s results have implications beyond just HATS-6 b. Because a planet’s temperature is folded into every calculation of what its atmosphere contains, a discrepancy this large raises questions about how reliably astronomers can read the atmospheres of planets orbiting small, active stars. 

For Guzmán Caloca and her team, many mysteries remain. Longer-wavelength observations could identify other unexplained signals and test whether clouds explain a planet's unexpectedly low temperature. Astronomers have found more than 6,000 planets beyond our solar system, and many of them look nothing like the ones closest to Earth. Reading their atmospheres—what they're made of, how they formed, which ones resemble Jupiter and which resemble nothing at all—can help scientists determine whether other solar systems were created through formation mechanisms similar to our own.

“What is our context? And how rare or how common are we?” Guzmán Caloca asked. “This is one planet out of thousands, but the way I like to think about it is that Earth is also one planet out of thousands and yet it holds everything that ever lived here.” 

###

The study, “GEMS JWST: Hold on to your HATS(-6 b), a sub-solar metallicity giant planet with water, methane and ammonia in its atmosphere,” was published in the Astronomical Journal on September 8, 2026.

This research was supported by NASA through a grant from the Space Telescope Science Institute for JWST program GO 3171, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract (NAS 5-03127). The observations were obtained from the Mikulski Archive for Space Telescopes (MAST) at STScI, with support for MAST for non-HST data provided by the NASA Office of Space Science (NNX09AF08G) and other grants and contracts. Additional support was provided by NASA Headquarters through an appointment to the NASA Postdoctoral Program at the Goddard Space Flight Center, administered by ORAU under contract with NASA, and under NASA award (80GSFC24M0006); by the National Science and Technology Council of Taiwan (114-2112-M-001-065-MY3); and by an Academia Sinica Career Development Award (AS-CDA-115-M03). The text does not necessarily represent the views of these organizations. 

 

Plant injury signals travel long distances in the root




University of Würzburg

Root System

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When plant roots are damaged, a shock wave spreads rapidly throughout the entire root system. Neighboring proteins detect the change and generate electrical signals. These signals trigger the synthesis of stress hormones.

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Credit: Angel Baudon






When plant roots are injured – by insects, for example – the hydraulic pressure of the root collapses, and this pressure wave spreads at high speed throughout the entire root system. In neighboring roots, tiny proteins that function like small mechanical pressure sensors detect the change and generate electrical and Calcium signals.

Ultimately, wounding induces the synthesis of stress hormones in the neighboring roots, causing them to prepare for the impending attack.

How plants communicate underground to defend their roots

These are the key findings of a new study recently published in the journal Science Advances. In this study, the authors examined the mechanisms that enable plants to signal root damage over long distances within the root.

The study was led by Dr. Angel Baudon, a postdoctoral researcher at the Julius von Sachs Institute at the University of Würzburg, as first author, and Professor Rainer Hedrich, former Chair of Botany I (Molecular Plant Physiology and Biophysics) at the University of Würzburg, as co-senior author.

For their study, the team investigated the signaling pathways of the model plant Arabidopsis thaliana (thale cress) in response to mechanical injury. “While the defense mechanisms of above-ground plant parts have already been extensively studied, communication within the root system remained a mystery for a long time,” says Angel Baudon, explaining the background of the work. Understanding root defense against pests such as insect larvae or nematodes is of crucial importance for agriculture, as hidden damage often leads to massive crop losses.

Pressure loss spreads at high speed

The study’s key finding demonstrates that plants use physical principles to propagate danger signals extremely quickly. “As soon as a root cell is injured, there is an immediate drop in intracellular pressure, which is very high in plants,” explains Dr. Baudon. This loss of pressure propagates as a hydraulic wave through the plant’s vascular system. Traveling at a speed of about 75 millimeters per second, this physical communication is roughly 10,000 times faster than the propagation of previously reported calcium waves. This enormous time advantage enables neighboring, still-intact roots to activate defense mechanisms early on.

The “alarm cascade” proceeds in several stages:

•    Mechanosensitive channels, known as MCA1 channels, act as primary decoders. MCA1 translates the physical stimulus of the mechanical pressure wave into electrical impulses and calcium signals.

•    Glutamate-like receptors (GLR3.3/3.6) act as essential amplifiers. They pick up the original signal and heighten the depolarization.

In this way, the information is passed on to other actors to initiate a wide-ranging immune response.

 

Calcium Signals Help Plants Prepare for Repeated Injury

Angel Baudon and his colleagues made another surprising discovery as part of this study: repeated bursts of calcium signals can make plant roots temporarily less sensitive to subsequent damage. Therefore, even if the plant still senses the injury, its reaction is reduced.

Using optogenetics to precisely trigger calcium signals in intact root cells without physically harming the plant, they found that plants exposed to repeated calcium signals showed much weaker electrical responses when later exposed to glutamate or wounded. The reduced response was observed not only in the wounded root but also in neighbouring roots, indicating that calcium signaling may help coordinate how plants respond to repeated or nearby damage.

Understanding Root Defense Mechanisms to Pave the Way for Agricultural Research

The study highlights that plants have developed specialized sensors for different organs. While the anion channel MSL10 plays a key role in the shoot, the calcium-ion-conducting channel MCA1 dominates in the root. The signal characteristics also follow their own logic: “In the leaves, warning signals often propagate over long distances without significant attenuation. In the root, however, the signal strength decreases exponentially with distance from the site of injury,” explains the researcher. This spatial limitation makes biological sense, he notes, since soil pests move significantly slower than insects on the leaf surface due to the compact nature of the soil.

According to the scientists, the newly gained knowledge about mechanical signal processing offers strategic approaches for agricultural research. “A deeper understanding of how crops perceive mechanical damage allows for a more targeted optimization of natural resistance to root-feeding insects,” explains Angel Baudon.

The identification of MCA1 as the primary decoder of the pressure drop uncovers a missing piece of the puzzle needed to decipher the complex defense strategies of underground organ systems and, in the long term, reduce dependence on chemical pesticides.

 

Nasal spray brings pain relief for children treated in the emergency department




European Society for Emergency Medicine (EUSEM)






Paris, France: A treatment for pain, that is delivered via a nasal spray, offers an effective, needle-free option for children being seen in the emergency department for a range of injuries, according to research presented at the European Emergency Medicine Congress today (Sunday) [1].

 

Researchers say that reducing pain quickly and effectively is especially important for children in the emergency department, yet there are currently very few treatment options available.

 

The research was presented by Professor Shammi Ramlakhan, an emergency medicine consultant working at Sheffield Children's Hospital, the University of Sheffield and Sheffield Hallam University in the UK.

 

He said: “Pain in children remains under-recognised and under-treated. Nearly a third of children with moderate to severe pain do not receive adequate pain relief within the 15 to 20 minutes recommended in international guidance. In this study we explored whether a combination of analgesic medication given in a simple dosing system would help provide quick and effective pain relief for children being treated in the emergency department.”

 

The research included 152 children aged between one and 17 with moderate to severe pain who were being treated at one of seven hospital emergency departments in the UK and Spain between May 2024 and May 2025 [2]. The majority had limb injuries, such as fractures and dislocations, while other children had burns or soft tissue injuries.

 

All children were given a combination of two pain relief medications, sufentanil and ketamine, via a nasal spray. The dose was adjusted according to the weight of each child by the number of puffs of the nasal spray. Children were assessed 15 minutes after being given the treatment and again after 30 minutes. The researchers used standard assessments to check how much pain children were in and to look for any side effects of the treatment.

 

After 15 minutes, more than half of the children (54%) were in less pain and after 30 minutes most of the children (88%) children were in less pain. Pain was reduced by around half in the majority of children (86.2%) 30 minutes after treatment. Side effects were mild and included nausea or vomiting, dizziness and nasal itching

 

Professor Ramlakhan said: “Our research shows that this drug can provide rapid and meaningful pain relief for children being treated in the emergency department. Children tolerated the nose spray well with no major side effects. This is good news for children and their families. This also gives doctors a simple and effective option for treating their patients where very few options currently exist.”

 

The nasal spray was being tested for the European Medicines Agency (EMA)’s paediatric-use marketing authorisation (PUMA) scheme, which aims to encourage manufacturers to develop and adapt medications specifically for children. Researchers say the treatment should be available for use in Europe in the near future.

 

Dr Maša Sorić is a member of the EUSEM abstract selection committee. She is head of the emergency department at University Hospital Merkur, Zagreb, Croatia, and was not involved with the research. She said: “Across Europe, we see millions of children in the emergency department every year. Many of these will be suffering painful injuries. Being in hospital can also be frightening for children and their families.

 

“This study assesses a nasal spray containing two existing types of pain relief with a very simple dosing system. The results suggest it helps to reduce pain quickly and effectively, without the need for an injection. The treatment did not cause too much drowsiness, and the side effects were mild.

 

“As doctors we want to give our patients effective treatments, and that includes treatment to reduce any pain they are suffering. However, the pain relief options that are currently available for children are limited at the moment, so we really need more treatments like this in the emergency department.”