Oct 1, 2022

Milky Way's graveyard of dead stars found

The first map of the 'galactic underworld' -- a chart of the corpses of once massive suns that have since collapsed into black holes and neutron stars -- has revealed a graveyard that stretches three times the height of the Milky Way, and that almost a third of the objects have been flung out from the galaxy altogether.

"These compact remnants of dead stars show a fundamentally different distribution and structure to the visible galaxy," said David Sweeney, a PhD student at the Sydney Institute for Astronomy at the University of Sydney, and lead author of the paper in the latest issue of Monthly Notices of the Royal Astronomical Society.

"The 'height' of the galactic underworld is over three times larger in the Milky Way itself," he added. "And an amazing 30 percent of objects have been completely ejected from the galaxy."

Neutron stars and black holes are formed when massive stars -- more than eight times larger than our Sun -- exhaust their fuel and suddenly collapse. This triggers a runaway reaction that blows the outer portions of the star apart in a titanic supernova explosion, while the core keeps compressing in on itself until -- depending on its starting mass -- it becomes either a neutron star or a black hole.

In neutron stars, the core is so dense that electrons and protons are forced to combine at the subatomic level into neutrons, squeezing its total mass into a sphere smaller than a city. If the mass of the original star is greater than 25 times our Sun's, that gravity-driven collapse continues, until the core is so dense that not even light can escape. Both types of stellar corpses warp space, time, and matter around them.

Although billions must have been formed since the galaxy was young, these exotic carcasses were flung out into the darkness of interstellar space by the supernova that created them, and hence slipped beyond sight and knowledge of astronomers -- until now.

By carefully recreating the full lifecycle of the ancient dead stars, the researchers have constructed the first detailed map showing where their corpses lie.

"One of the problems for finding these ancient objects is that, until now, we had no idea where to look," said Sydney Institute for Astronomy's Professor Peter Tuthill, co-author on the paper. "The oldest neutron stars and black holes were created when the galaxy was younger and shaped differently, and then subjected to complex changes spanning billions of years. It has been a major task to model all of this to find them."

Newly-formed neutron stars and black holes conform to today's galaxy, so astronomers know where to look. But the oldest neutron stars and black holes are like ghosts still haunting a house demolished long ago, so they are harder to find.

"It was like trying to find the mythical elephant's graveyard," said Professor Tuthill, referring to a place where, according to legend, old elephants go to die alone, far from their group. "The bones of these rare massive stars had to be out there, but they seemed to shroud themselves in mystery."

Added Sweeney: "The hardest problem I had to solve in hunting down their true distribution was to account for the 'kicks' they receive in the violent moments of their creation. Supernova explosions are asymmetric, and the remnants are ejected at high speed -- up to millions of kilometres per hour -- and, even worse, this happens in an unknown and random direction for every object."

But nothing in the universe sits still for long, so even knowing the likely magnitudes of the explosive kicks was not enough: the researchers had to delve into the depths of cosmic time and reconstruct how they behaved over billions of years.

"It's a little like in snooker," said Sweeney. "If you know which direction the ball is hit, and how hard, then you can work out where it will end up. But in space, the objects and speeds are just vastly bigger. Plus, the table's not flat, so the stellar remnants go on complex orbits threading through the galaxy.

"Finally, unlike a snooker table, there is no friction -- so they never slow down. Almost all the remnants ever formed are still out there, sliding like ghosts through interstellar space."

The intricate models they built -- together with University of Sydney Research Fellow Dr Sanjib Sharma and Dr Ryosuke Hirai of Monash University -- encoded where the stars were born, where they met their fiery end and their eventual dispersal as the galaxy evolved.

The final outcome is a distribution map of the Milky Way's stellar necropolis.

"It was a bit of a shock," said Dr Sharma. "I work every day with images of the visible galaxy we know today, and I expected that the galactic underworld would be subtly different, but similar in broad strokes. I was not expecting such a radical change in form."

In the maps generated, the characteristic spiral arms of the Milky Way vanish in the 'galactic underworld' version. These are entirely washed out because of the age of most of the remnants, and the blurring effects of the energetic kicks from the supernovae which created them.

Even more intriguing, the side-on view shows that the galactic underworld is much more 'puffed up' than the Milky Way -- a result of kinetic energy injected by supernovae elevating them into a halo around the visible Milky Way.

"Perhaps the most surprising finding from our study is that the kicks are so strong that the Milky Way will lose some of these remnants entirely," said Dr Hirai. "They are kicked so hard that about 30 percent of the neutron stars are flung out into intergalactic space, never to return."

Added Tuthill: "For me, one of the coolest things we found in this work is that even the local stellar neighbourhood around our Sun is likely to have these ghostly visitors passing through. Statistically our nearest remnant should be only 65 light years away: more or less in our backyard, in galactic terms."

Read more at Science Daily

How fish survive the extreme pressures of life in the oceans

Scientists have discovered how a chemical in the cells of marine organisms enables them to survive the high pressures found in the deep oceans.

The deeper sea creatures live, the more inhospitable and extreme the environment they must cope with. In one of the deepest points in the Pacific -- the Mariana Trench, 11 kilometers below the sea surface -- the pressure is 1.1 kbar or eight tons per square inch. That is a 1,100-fold increase of the pressure experienced at the Earth's surface.

Under normal or atmospheric pressure, water molecules form a tetrahedron-like network.

Network of water molecules changes shape

At high pressure, though, the network of water molecules begins to distort and change shape. When this happens to the water inside living cells, it prevents vital bio-chemical processes from taking place -- and kills the organism.

In reporting their findings, the researchers in Leeds have for the first time been able to provide an explanation of how a molecule found in the cells of marine organisms counteracts the effect of external pressure on the water molecules.

Professor Lorna Dougan, from the School of Physics and Astronomy at Leeds, said: "Life has adapted to survive and thrive in environmental extremes. In the depths of the oceans, organisms live under extreme high pressures that would destroy human life.

"These high pressures distort the liquid water that resides in all life, resulting in detrimental impacts to the biomolecules that underpin all biological processes.

"We need to understand what happens to water under pressure and how pressure-adapted organisms combat these effects. If we can understand how these organisms survive at extreme pressure, we can apply these findings to the wider study of biomolecular stability."

Trimethylamine N-oxide or TMAO


The molecule found in cells that produces the protective effect against high external pressure is called TMAO -- trimethylamine N-oxide. Studies have shown that the amount of TMAO in ocean-dwelling organisms increases in line with the depth of their habitat.

Led by Dr Harrison Laurent, also from the School of Physics and Astronomy, the study used one of the most advanced analytical facilities in the world to investigate how intense pressure alters the hydrogen bonds between neighbouring water molecules.

Neutron scattering

Called the ISIS Neutron and Muon Source, the analytical facility at the STFC Rutherford Appleton Laboratory in Oxfordshire was used to fire a beam of neutrons -- which are sub-atomic particles -- at samples of water with and without TMAO. The analysis was done at low pressure, 25 bar, and at high pressure, 4 kbar.

The test revealed details of the atomic structure of the water molecules.

At high pressure, the hydrogen bonds in the pure water sample became distorted and less stable and the overall network of water molecules became compacted.

The presence of TMAO, however, strengthened and stabilised the hydrogen bonding and maintained the network structure of the water molecules.

Dr Laurent said: "The TMAO provides a structural anchor which results in the water being able to resist the extreme pressure it is under. The findings are important because they help scientists understand the processes by which organisms have adapted to survive the extreme conditions found in the oceans."

From the study, the research team have also been able to develop what is called an "osmolyte protection ratio," which predicts the level of TMAO needed in the cells of marine organisms so they can survive at a specific depth in the oceans.

Professor Dougan added: "Professor Dougan added: "Our study provides a bridge between water under pressure at the molecular level and the wonderful ability of organisms which thrive under high pressure in depths of the oceans.

Read more at Science Daily

Sep 30, 2022

Webb reveals a galaxy sparkling with the universe's oldest star clusters

Using the James Webb Space Telescope (JWST), researchers from the CAnadian NIRISS Unbiased Cluster Survey (CANUCS) team have identified the most distant globular clusters ever discovered. These dense groups of millions of stars may be relics that contain the first and oldest stars in the universe.

The early analysis of Webb's First Deep Field image, which depicts some of the universe's earliest galaxies, is published today in The Astrophysical Journal Letters.

"JWST was built to find the first stars and the first galaxies and to help us understand the origins of complexity in the universe, such as the chemical elements and the building blocks of life," says Lamiya Mowla, Dunlap Fellow at the Dunlap Institute for Astronomy & Astrophysics at the University of Toronto and co-lead author of the study. "This discovery in Webb's First Deep Field is already providing a detailed look at the earliest phase of star formation, confirming the incredible power of JWST."

In the finely detailed Webb's First Deep Field image, the researchers zeroed in on what they've dubbed "the Sparkler galaxy," which is nine billion light years away. This galaxy got its name for the compact objects appearing as small yellow-red dots surrounding it, referred to by the researchers as "sparkles." The team posited that these sparkles could either be young clusters actively forming stars -- born three billion years after the Big Bang at the peak of star formation -- or old globular clusters. Globular clusters are ancient collections of stars from a galaxy's infancy and contain clues about its earliest phases of formation and growth.

From their initial analysis of 12 of these compact objects, the researchers determined that five of them are not only globular clusters but among the oldest ones known.

"Looking at the first images from JWST and discovering old globular clusters around distant galaxies was an incredible moment, one that wasn't possible with previous Hubble Space Telescope imaging," says Kartheik G. Iyer, Dunlap Fellow at the Dunlap Institute for Astronomy & Astrophysics at the University of Toronto and co-lead author of the study. "Since we could observe the sparkles across a range of wavelengths, we could model them and better understand their physical properties, like how old they are and how many stars they contain. We hope the knowledge that globular clusters can be observed at from such great distances with JWST will spur further science and searches for similar objects."

The Milky Way galaxy has about 150 globular clusters, and how and when exactly these dense clumps of stars formed is not well understood. Astronomers know that globular clusters can be extremely old, but it is incredibly challenging to measure their ages. Using very distant globular clusters to age-date the first stars in distant galaxies has not been done before and is only possible with JWST.

"These newly identified clusters were formed close to the first time it was even possible to form stars," says Mowla. "Because the Sparkler galaxy is much farther away than our own Milky Way, it is easier to determine the ages of its globular clusters. We are observing the Sparkler as it was nine billion years ago, when the universe was only four-and-a-half billion years old, looking at something that happened a long time ago. Think of it as guessing a person's age based on their appearance -- it's easy to tell the difference between a 5- and 10-year-old, but hard to tell the difference between a 50- and 55-year-old."

Until now, astronomers could not see the surrounding compact objects of the Sparkler galaxy with the Hubble Space Telescope (HST). This changed with JWST's increased resolution and sensitivity, unveiling the tiny dots surrounding the galaxy for the first time in Webb's First Deep Field image. The Sparkler galaxy is special because it is magnified by a factor of 100 due to an effect called gravitational lensing -- where the SMACS 0723 galaxy cluster in the foreground distorts what is behind it, much like a giant magnifying glass. Moreover, gravitational lensing produces three separate images of the Sparkler, allowing astronomers to study the galaxy in greater detail.

"Our study of the Sparkler highlights the tremendous power in combining the unique capabilities of JWST with the natural magnification afforded by gravitational lensing," says CANUCS team lead Chris Willott from the National Research Council's Herzberg Astronomy and Astrophysics Research Centre. "The team is excited about more discoveries to come when JWST turns its eye on the CANUCS galaxy clusters next month."

The researchers combined new data from JWST's Near-Infrared Camera (NIRCam) with HST archival data. NIRCam detects faint objects using longer and redder wavelengths to observe past what is visible to the human eye and even HST. Both magnifications due to the lensing by the galaxy cluster and the high resolution of JWST are what made observing compact objects possible.

The Canadian-made Near-Infrared Imager and Slitless Spectrograph (NIRISS) instrument on the JWST provided independent confirmationthat the objects are old globular clusters because the researchers did not observe oxygen emission lines -- emissions with measurable spectra given off by young clusters that are actively forming stars. NIRISS also helped unravel the geometry of the triply lensed images of the Sparkler.

"JWST's made-in-Canada NIRISS instrument was vital in helping us understand how the three images of the Sparkler and its globular clusters are connected," says Marcin Sawicki, Canada Research Chair in Astronomy, professor at Saint Mary's University and study co-author. "Seeing several of the Sparkler's globular clusters imaged three times made it clear that they are orbiting around the Sparkler galaxy rather than being simply in front of it by chance."

JWST will observe the CANUCS fields starting in October 2022, leveraging JWST data to examine five massive clusters of galaxies, around which the researchers expect to find more such systems. Future studies will also model the galaxy cluster to understand the lensing effect and execute more robust analyses to explain the star formation histories.

Read more at Science Daily

Dead fish breathes new life into the evolutionary origin of fins and limbs

A trove of fossils in China, unearthed in rock dating back some 436 million years, have revealed for the first time that the mysterious galeaspids, a jawless freshwater fish, possessed paired fins.

The discovery, by an international team, led by Min Zhu of the Institute of Vertebrate Palaeontology and Palaeoanthropology, Bejiing and Professor Philip Donoghue from the University of Bristol's School of Earth Sciences, shows the primitive condition of paired fins before they separated into pectoral and pelvic fins, the forerunner to arms and legs.

Until now, the only surviving fossils of galeaspids were heads, but these new fossils originating in the rocks of Hunan Province and Chongqing and named Tujiaaspis after the indigenous Tujia people who live in this region, contain their whole bodies.

Theories abound on the evolutionary beginnings of vertebrate fins and limbs -- the evolutionary precursors of arms and legs -- mostly based on comparative embryology. There is a rich fossil record, but early vertebrates either had fins or they didn't. There was little evidence for their gradual evolution.

First author Zhikun Gai, a University of Bristol alumnus, said: "The anatomy of galeaspids has been something of a mystery since they were first discovered more than half a century ago. Tens of thousands of fossils are known from China and Vietnam, but almost all of them are just heads -- nothing has been known about the rest of their bodies -- until now.

"The new fossils are spectacular, preserving the whole body for the first time and revealing that these animals possessed paired fins that extended continuously, all the way from the back of the head to the very tip of the tail. This is a great surprise since galeaspids have been thought to lack paired fins altogether."

Corresponding author Professor Donoghue said: "Tujiaaspis breathes new life into a century old hypothesis for the evolution of paired fins, through differentiation of pectoral (arms) and pelvic (legs) fins over evolutionary time from a continuous head-to-tail fin precursor.

"This 'fin-fold' hypothesis has been very popular but it has lacked any supporting evidence until now. The discovery to Tujiaaspis resurrects the fin-fold hypothesis and reconciles it with contemporary data on the genetic controls on the embryonic development of fins in living vertebrates."

Corresponding author Min Zhu of VPP, Beijing, added "Tujiaaspis shows the primitive condition for paired fins first evolved. Later groups, like the jawless osteostracans show the first evidence for the separation of muscular pectoral fins, retaining long pelvic fins that reduced to the short muscular fins in jawed vertebrates, such as in groups like placoderms and sharks. Nevertheless, we can see vestiges of elongate fin-folds in the embryos of living jawed fishes, which can be experimentally manipulated to reproduce them. The key question is why did fins first evolve in this way?"

Bristol's Dr Humberto Ferron used computational engineering approaches to simulate the behaviour of models of Tujiaaspis with and without the paired fins. The co-author said: "The paired fins of Tujiaaspis act as hydrofoils, passively generating lift for the fish without any muscular input from the fins themselves. The lateral fin-folds of Tujiaaspis allowed it to swim more efficiently."

Co-author Dr Joseph Keating at Bristol modelled the evolution of paired fins. He said: "Fossil jawless vertebrates display a dizzying array of fin types, which has provoked extensive debate about the evolution of paired fins.

Read more at Science Daily

System to create bioplastics

A team of Texas A&M AgriLife Research scientists has developed a system that uses carbon dioxide, CO2, to produce biodegradable plastics, or bioplastics, that could replace the nondegradable plastics used today. The research addresses two challenges: the accumulation of nondegradable plastics and the remediation of greenhouse gas emissions.

Published Sept. 28 in Chem, the research was a collaboration of Susie Dai, Ph.D., associate professor in the Texas A&M Department of Plant Pathology and Microbiology, and Joshua Yuan, Ph.D., formerly with the Texas A&M Department of Plant Pathology and Microbiology as chair for synthetic biology and renewable products and now Lopata professor and chair in the Washington University in St. Louis Department of Energy, Environmental and Chemical Engineering.

The research was made possible by the John '90 and Sally '92 Hood Fund for Sustainability and Renewable Products, Texas A&M AgriLife and Texas A&M University.

Creating bioplastics

Dai said today's petroleum-based plastics do not degrade easily and create a massive issue in the ecosystems and, ultimately, oceans.

To address these issues, the Texas A&M College of Agriculture and Life Sciences researchers and their teams worked for almost two years to develop an integrated system that uses CO2 as a feedstock for bacteria to grow in a nutrient solution and produce bioplastics. Peng Zhang, Ph.D., postdoctoral research associate, and Kainan Chen, doctoral student, both in the Texas A&M Department of Plant Pathology and Microbiology, contributed to the work. The Texas A&M University System has filed a patent application for the integrated system.

"Carbon dioxide has been used in concert with bacteria to produce many chemicals, including bioplastics, but this design produces a highly efficient, smooth flow through our carbon dioxide-to-bioplastics pipeline," Dai said.

"In theory, it is kind of like a train with units connected to each other," Dai said. "The first unit uses electricity to convert the carbon dioxide to ethanol and other two-carbon molecules -- a process called electrocatalysis. In the second unit, the bacteria consume the ethanol and carbon molecules to become a machine to produce bioplastics, which are different from petroleum-based plastic polymers that are harder to degrade."

Capturing and re-using CO2 waste


Using CO2 in the process could also help reduce greenhouse gas emissions. Many manufacturing processes emit CO2 as a waste product.

"If we can capture the waste carbon dioxide, we reduce greenhouse gas emission and can use it as a feedstock to produce something," Dai said. "This new platform has great potential to address sustainability challenges and transform the future design of carbon dioxide reduction."

The major strength of the new platform is a much faster reaction rate than photosynthesis and higher energy efficiency.

"We are expanding the capacity of this platform to broad product areas such as fuels, commodity chemicals and diverse materials," Dai said. "The study demonstrated the blueprint for 'decarbonized biomanufacturing' that could transform our manufacturing sector."

Expanding future impacts

Dai said currently, bioplastics are more expensive than petroleum-based plastics. But if the technology is successful enough to produce bioplastics at an economic scale, industries could replace traditional plastic products with ones that have fewer negative environmental impacts. In addition, mitigating CO2 emissions from energy sectors such as gas and electric facilities would also be a benefit.

Read more at Science Daily

Scientists find link between fast-melting Arctic ice and ocean acidification

An international team of researchers have sounded new alarm bells about the changing chemistry of the western region of the Arctic Ocean after discovering acidity levels increasing three to four times faster than ocean waters elsewhere.

The team, which includes University of Delaware marine chemistry expert Wei-Jun Cai, also identified a strong correlation between the accelerated rate of melting ice in the region and the rate of ocean acidification, a perilous combination that threatens the survival of plants, shellfish, coral reefs and other marine life and biological processes throughout the planet's ecosystem.

The new study, published on Thursday, Sept. 30 in Science, the flagship journal of the American Association for the Advancement of Science, is the first analysis of Arctic acidification that includes data from more than two decades, spanning the period from 1994 to 2020.

Scientists have predicted that by 2050 -- if not sooner -- Arctic sea ice in this region will no longer survive the increasingly warm summer seasons. As a result of this sea-ice retreat each summer, the ocean's chemistry will grow more acidic, with no persistent ice cover to slow or otherwise mitigate the advance.

That creates life-threatening problems for the enormously diverse population of sea creatures, plants and other living things that depend on a healthy ocean for survival. Crabs, for example, live in a crusty shell built from the calcium carbonate prevalent in ocean water. Polar bears rely on healthy fish populations for food, fish and sea birds rely on plankton and plants, and seafood is a key element of many humans' diets.

That makes acidification of these distant waters a big deal for many of the planet's inhabitants.

First, a quick refresher course on pH levels, which indicate how acidic or alkaline a given liquid is. Any liquid that contains water can be characterized by its pH level, which ranges from 0 to 14, with pure water considered neutral with a pH of 7. All levels lower than 7 are acidic, all levels greater than 7 are basic or alkaline, with each full step representing a tenfold difference in the hydrogen ion concentration. Examples on the acidic side include battery acid, which checks in at 0 pH, gastric acid (1), black coffee (5) and milk (6.5). Tilting toward basic are blood (7.4), baking soda (9.5), ammonia (11) and drain cleaner (14). Seawater is normally alkaline, with a pH value of around 8.1.

Cai, the Mary A.S. Lighthipe Professor in the School of Marine Science and Policy in UD's College of Earth, Ocean and Environment, has published significant research on the changing chemistry of the planet's oceans and this month completed a cruise from Nova Scotia to Florida, serving as chief scientist among 27 aboard the research vessel. The work, supported by the National Oceanic and Atmospheric Administration (NOAA), includes four areas of study: The East Coast, the Gulf of Mexico, the Pacific Coast and the Alaska/Arctic region.

The new study in Science included UD postdoctoral researcher Zhangxian Ouyang, who participated in a recent voyage to collect data in the Chukchi Sea and Canada Basin in the Arctic Ocean.

The first author on the publication was Di Qi, who works with Chinese research institutes in Xiamen and Qingdao. Also collaborating on this publication were scientists from Seattle, Sweden, Russia and six other Chinese research sites.

"You can't just go by yourself," Cai said. "This international collaboration is very important for collecting long-term data over a large area in the remote ocean. In recent years, we have also collaborated with Japanese scientists as accessing the Arctic water was even harder in the past three years due to COVID-19. And we always have European scientists participating."

Cai said he and Qi both were baffled when they first reviewed the Arctic data together during a conference in Shanghai. The acidity of the water was increasing three to four times faster than ocean waters elsewhere.

That was stunning indeed. But why was it happening?

Cai soon identified a prime suspect: the increased melt of sea ice during the Arctic's summer season.

Historically, the Arctic's sea ice has melted in shallow marginal regions during the summer seasons. That started to change in the 1980s, Cai said, but waxed and waned periodically. In the past 15 years, the ice melt has accelerated, advancing into the deep basin in the north.

For a while, scientists thought the melting ice could provide a promising "carbon sink," where carbon dioxide from the atmosphere would be sucked into the cold, carbon-hungry waters that had been hidden under the ice. That cold water would hold more carbon dioxide than warmer waters could and might help to offset the effects of increased carbon dioxide elsewhere in the atmosphere.

When Cai first studied the Arctic Ocean in 2008, he saw that the ice had melted beyond the Chukchi Sea in the northwest corner of the region, all the way to the Canada Basin -- far beyond its typical range. He and his collaborators found that the fresh meltwater did not mix into deeper waters, which would have diluted the carbon dioxide. Instead, the surface water soaked up the carbon dioxide until it reached about the same levels as in the atmosphere and then stopped collecting it. They reported this result in a paper in Science in 2010.

That would also change the pH level of the Arctic waters, they knew, reducing the alkaline levels of the seawater and reducing its ability to resist acidification. But how much? And how soon? It took them another decade to collect enough data to derive a sound conclusion on the long-term acidification trend.

Analyzing data gathered from 1994 to 2020 -- the first time such a long-term perspective was possible -- Cai, Qi and their collaborators found an extraordinary increase in acidification and a strong correlation with the increasing rate of melting ice.

They point to sea-ice melt as the key mechanism to explain this rapid pH decrease, because it changes the physics and chemistry of the surface water in three primary ways:
 

  • The water under the sea ice, which had a deficit of carbon dioxide, now is exposed to the atmospheric carbon dioxide and can take up carbon dioxide freely.
     
  • The seawater mixed with meltwater is light and cannot mix easily into deeper waters, which means the carbon dioxide taken from the atmosphere is concentrated at the surface.
     
  • The meltwater dilutes the carbonate ion concentration in the seawater, weakening its ability to neutralize the carbon dioxide into bicarbonate and rapidly decreasing ocean pH.


Cai said more research is required to further refine the above mechanism and better predict future changes, but the data so far show again the far-reaching ripple effects of climate change.

"If all of the multiple-year ice is replaced by first-year ice, then there will be lower alkalinity and lower buffer capacity and acidification continues," he said. "By 2050, we think all of the ice will be gone in the summer. Some papers predict that will happen by 2030. And if we follow the current trend for 20 more years, the summer acidification will be really, really strong."

Read more at Science Daily

Sep 29, 2022

Astronomers map distances to 56,000 galaxies, largest-ever catalog

How old is our universe, and what is its size? A team of researchers led by University of Hawaii at Manoa astronomers Brent Tully and Ehsan Kourkchi from the Institute for Astronomy have assembled the largest-ever compilation of high-precision galaxy distances, called Cosmicflows-4. Using eight different methods, they measured the distances to a whopping 56,000 galaxies. The study has been published in the Astrophysical Journal.

Galaxies, such as the Milky Way, are the building blocks of the universe, each comprised of up to several hundred billion stars. Galaxies beyond our immediate neighborhood are rushing away, faster if they are more distant, which is a consequence of the expansion of the universe that began at the moment of the Big Bang. Measurements of the distances of galaxies, coupled with information about their velocities away from us, determine the scale of the universe and the time that has elapsed since its birth.

"Since galaxies were identified as separate from the Milky Way a hundred years ago, astronomers have been trying to measure their distances," said Tully. "Now by combining our more accurate and abundant tools, we are able to measure distances of galaxies, and the related expansion rate of the universe and the time since the universe was born with a precision of a few percent."

From the newly published measurements, the researchers derived the expansion rate of the universe, called the Hubble Constant, or H0. The team's study gives a value of H0=75 kilometers per second per megaparsec or Mpc (1 megaparsec = 3.26 million light years), with very small statistical uncertainty of about 1.5%.

There are a number of ways to measure galaxy distances. Generally, individual researchers focus on an individual method. The Cosmicflows program spearheaded by Tully and Kourkchiincludes their own original material from two methods, and additionally

incorporates information from many previous studies. Because Cosmicflows-4 includes distances derived from a variety of independent, distinct distance estimators, intercomparisons should mitigate against a large systematic error.

Cosmic dilemma

Astronomers have assembled a framework that shows the universe's age to be a little more than 13 billion years old, however a dilemma of great significance has arisen in the details.

Physics of the evolution of the universe based on the standard model of cosmology predicts H0=67.5 km/s/Mpc, with an uncertainty of 1 km/s/Mpc. The difference between the measured and predicted values for the Hubble Constant is 7.5 km/s/Mpc -- much more than can be expected given the statistical uncertainties. Either there is a fundamental problem with our understanding of the physics of the cosmos, or there is a hidden systematic error in the measurements of galaxy distances.

Additional studies


Cosmicflows-4 is also being used to study how galaxies move individually, in addition to flowing with the overall expansion of the universe. Deviations from this smooth expansion arise due to the gravitational influences of clumps of matter, on scales ranging from our Earth and Sun up to congregations of galaxies on scales of a half billion light years. The mysterious dark matter is the dominant component on larger scales. With knowledge of the motions of galaxies in response to the mass around them, we can recreate the orbits that galaxies have followed since they were formed, giving us a better understanding of how the universe's vast, dark-matter dominated structures have formed over the eons of time.

From Science Daily

The neighbors of the caliph: Archaeologists uncover ancient mosaics on the shore of the Sea of Galilee

With the help of geomagnetic surface surveys and subsequent hands-on digging, an excavation team from Johannes Gutenberg University Mainz (JGU) has revealed new insights into the area in which the caliph's palace of Khirbat al-Minya was built on the shores of the Sea of Galilee. According to these findings, there had already been a settlement occupied by Christian or Jewish inhabitants in the immediate vicinity long before the palace was built.

"This time we have really hit the jackpot with our excavations," said site director and archaeologist Professor Hans-Peter Kuhnen with regard to the outcome of the most recent undertakings in the area around the early Islamic caliph's palace Khirbat al-Minya in Israel. The team of archaeologists from Mainz made this major discovery using geomagnetic methods and by digging test pits on the basis of the findings. They discovered that in the early 8th century the caliph had commissioned the building of his palace, with its incorporated mosque and a 15-meter-high gateway tower, not -- as hitherto suspected -- on greenfield land on the unoccupied shore of the Sea of Galilee, but adjacent to and respectfully co-existing with a prior settlement. The research project was initially conceived as a means of training students in archeological field work. It was undertaken with the support of the Israel Antiquities Authority and financed by the Fritz Thyssen Foundation, the Axel Springer Foundation, the Santander Foundation, and the German Academic Exchange Service (DAAD). The team was accommodated in the Tabgha Pilgerhaus guesthouse run by the German Association of the Holy Land (DVHL), which has owned the site of the excavations on the northwest shore of the Sea of Galilee since 1895.

During their dig, the Mainz archaeological team found stone structures made of basalt dating to various periods, with plastered walls, colorful mosaic floors, and a water cistern. The plants portrayed in one of the mosaics are particularly remarkable as they have the long, curved stems typical of those also depicted in so-called Nile-scene mosaics created in the 5th to 6th centuries. The mosaic's images of the flora and fauna native to the Nile valley symbolized the life-giving power of the mighty river with its annual floods guaranteeing Egypt's agricultural fertility. That explains why both late-antique churches, such as that in the nearby Church of the Multiplication in Tabgha, and luxurious dwellings in cities of late antiquity were decorated with Nile-scene mosaics.

Lakeside settlement was there long before the caliph's palace was planned

The recently discovered mosaic, together with related ceramic finds dating to the 5th to 7th centuries, show that the settlement on the shores of the lake was already thriving centuries before the work on the caliph's palace had commenced. Its original inhabitants were either Christians or Jews and they were subsequently joined by a small Islamic community, for whom the caliph had a side entrance constructed in the early 8th century so that they could access his palace mosque. The unearthed ceramics have revealed that the site remained occupied under the control of the Umayyad and then Abbasid caliphates from the 7th to the 11th century. New construction projects were initiated in this period during which parts of the mosaics fell victim to pickaxes wielded by religiously inspired iconoclasts, sections of old walls were demolished, and the stones were transported away for reuse elsewhere. The remains finally became the location of a graveyard in which the dead were buried, in accordance with Muslim custom, lying on their side with their faces directed towards Mecca.

Nearby, the Mainz team also exposed a stone built furnace used to process sugar cane. Although sugar cane represented one of the top agricultural exports of the Holy Land from the period of the early Middle Ages and brought in considerable wealth for the landowners, vast volumes of water were needed to cultivate it while large amounts of wood were required to operate boiling furnaces. The result was extensive soil erosion and an environmental disaster that the area around the lake had not fully recovered from even by the 20th century. The immense scale of sugarcane cultivation in the Middle Ages was demonstrated by both the findings of the excavations at the Caliph's Palace -- those from 1936 to 1939 and those in 2016 -- and by the 2019 Mainz geomagnetic surveys, which all revealed evidence of dozens of such furnaces in operation between the 12th and 13th/14th centuries. "Our most recent excavations show that Caliph Walid had his palace built on the shore of the Sea of Galilee in an already carefully structured landscape that had long been inhabited. It was here that considerable money was subsequently made through the cultivation of sugar cane, sadly causing lasting damage to the ecosystem," said Kuhnen. "Our research has brought this settlement adjacent to the caliph's palace to light again, putting it in its rightful context among the history of human settlement of the Holy Land. Over the centuries, it experienced alternating periods of innovation and decline, but there was no real disruption to its existence during its lifetime."

Geomagnetic surface surveys showed where to dig

The Mainz-based team was able to locate this historic hotspot so accurately with its test pits due to the results of geomagnetic surface surveys conducted on-site in a pilot project in 2019. The technology employs magnetic sensors to detect and map tiny variations in the Earth's magnetic field caused by soil disturbances, for example those caused by construction work. This allows archaeologists to predict with a fair degree of confidence the course of walls and flooring and to identify the site of hearths and ovens hidden under the soil, without recourse to a spade. However, to actually verify whether magnetometry results indeed indicate the presence of something interesting and in order to date the potential structures, archaeologists need to dig targeted test pits -- as did the team from JGU's Department of Ancient Studies at Khirbat al-Minya.

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Revealing the genome of the common ancestor of all mammals

An international team has reconstructed the genome organization of the earliest common ancestor of all mammals. The reconstructed ancestral genome could help in understanding the evolution of mammals and in conservation of modern animals. The earliest mammal ancestor likely looked like the fossil animal "Morganucodon" which lived about 200 million years ago. The work is published the scientific journal Proceedings of the National Academy of Sciences.

Every modern mammal, from a platypus to a blue whale, is descended from a common ancestor that lived about 180 million years ago. We don't know a great deal about this animal, but the organization of its genome has now been computationally reconstructed by an international team of scientists.

"Our results have important implications for understanding the evolution of mammals and for conservation efforts," says Harris Lewin, distinguished professor of evolution and ecology at the University of California, Davis, and senior author on the paper.

The scientists drew on high-quality genome sequences from 32 living species representing 23 of the 26 known orders of mammals. They included humans and chimps, wombats and rabbits, manatees, domestic cattle, rhinos, bats and pangolins. The analysis also included the chicken and Chinese alligator genomes as comparison groups. Some of these genomes are being produced as part of the Earth BioGenome Project and other large-scale biodiversity genome sequencing efforts. Lewin chairs the Working Group for the Earth BioGenome Project.

The reconstruction shows that the mammal ancestor had 19 autosomal chromosomes, which control the inheritance of an organism's characteristics outside of those controlled by sex-linked chromosomes, (these are paired in most cells, making 38 in total) plus two sex chromosomes, said Joana Damas, first author on the study and a postdoctoral scientist at the UC Davis Genome Center. The team identified 1,215 blocks of genes that consistently occur on the same chromosome in the same order across all 32 genomes. These building blocks of all mammal genomes contain genes that are critical to developing a normal embryo.

Chromosomes stable over 300 million years

The scientists found nine whole chromosomes, or chromosome fragments in the mammal ancestor whose order of genes is the same in modern birds' chromosomes.

"This remarkable finding shows the evolutionary stability of the order and orientation of genes on chromosomes over an extended evolutionary timeframe of more than 320 million years," Lewin says. In contrast, regions between these conserved blocks contained more repetitive sequences and were more prone to breakages, rearrangements and sequence duplications, which are major drivers of genome evolution.

"Ancestral genome reconstructions are critical to interpreting where and why selective pressures vary across genomes. This study establishes a clear relationship between chromatin architecture, gene regulation and linkage conservation," says Professor William Murphy, Texas A&M University, who was not an author on the paper. "This provides the foundation for assessing the role of natural selection in chromosome evolution across the mammalian tree of life."

The scientists were able to follow the ancestral chromosomes forward in time from the common ancestor. They found that the rate of chromosome rearrangement differed between mammal lineages. For example, in the ruminant lineage (leading to modern cattle, sheep and deer) there was an acceleration in rearrangement 66 million years ago, when an asteroid impact killed off the dinosaurs and led to the rise of mammals.

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Study demonstrates that ticks weaken skin's immune response

Hitherto, scientists have not fully understood why ticks are such dangerous disease vectors. A research team led by Johanna Strobl and Georg Stary from MedUni Vienna's Department of Dermatology shows that tick saliva inhibits the skin's defence function, thereby increasing the risk of diseases such as tick-borne encephalitis (TBE) or Lyme disease. The study was recently published in the Journal of Clinical Investigation.

The researchers carried out their investigations on skin samples from volunteers and also on models of human skin, mimicking the bite of the most common European tick (Ixodes ricinus). In both cases, the team led by Georg Stary (MedUni Vienna's Department of Dermatology, CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases) in collaboration with the research group of Hannes Stockinger (Center for Pathophysiology, Infectiology and Immunology at MedUni Vienna) identified rapidly occurring patterns of immunomodulation. For example, it was found that the function of immune cells, especially T cells, which are important for immunological memory, was disrupted by contact with tick saliva.

Tick saliva modulates immune system

The scientists made similar observations in early stages of model infection by Borrelia burgdorferi, the most common cause of Lyme disease. They found that pre-incubation of Lyme disease-transmitting bacteria (B. burgdorferi spirochetes) with tick salivary gland extracts impedes the accumulation of immune cells in the skin and increases the pathogen burden. "Overall, we found that tick feeding causes profound changes in the skin's immune system inhibiting the local immune response. This means that dangerous pathogens that are introduced into the skin together with tick saliva, can multiply more easily, leading to infection," says Johanna Strobl, lead author of the study, summarising the main research findings.

Climate change increases danger from ticks

Austria is one of the countries with the greatest prevalence of ticks. Nearly every second European tick is infected with pathogens, Lyme disease and tick-borne encephalitis (TBE) being the most common tick-borne diseases. The arachnids become active at a temperature of seven degrees. Due to rising temperatures associated with climate change, ticks now also pose a threat in higher-altitude regions of Austria and well into late autumn.

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Sep 28, 2022

Dozens of newly discovered gravitational lenses could reveal ancient galaxies and the nature of dark matter

Earlier this year a machine learning algorithm identified up to 5,000 potential gravitational lenses that could transform our ability to chart the evolution of galaxies since the Big Bang.

Now astronomer Kim-Vy Tran from ASTRO 3D and UNSW Sydney and colleagues have assessed 77 of the lenses using the Keck Observatory in Hawai'i and Very Large Telescope in Chile. She and her international team confirmed that 68 out of the 77 are strong gravitational lenses spanning vast cosmic distances.

This success rate of 88 per cent suggests that the algorithm is reliable and that we could have thousands of new gravitational lenses. To date, gravitational lenses have been hard to find and only about a hundred are routinely used.

Kim-Vy Tran's paper published today in the Astronomical Journal presents spectroscopic confirmation of strong gravitational lenses previously identified using Convolutional Neural Networks, developed by data scientist Dr Colin Jacobs at ASTRO 3D and Swinburne University.

The work is part of the ASTRO 3D Galaxy Evolution with Lenses (AGEL) survey.

"Our spectroscopy allowed us to map a 3D picture of the gravitational lenses to show they are genuine and not merely chance superposition," says corresponding author Dr. Tran from the ARC Centre of Excellence for All Sky Astrophysics in 3-Dimensions (ASTRO3D) and the University of NSW (UNSW).

"Our goal with AGEL is to spectroscopically confirm around 100 strong gravitational lenses that can be observed from both the Northern and Southern hemispheres throughout the year," she says.

The paper is the result of a collaboration spanning the globe with researchers from Australia, the United States, the United Kingdom, and Chile.

The work was made possible by the development of the algorithm to look for certain digital signatures.

"With that we could identify many thousands of lenses compared to just a few handfuls," says Dr. Tran.

Gravitational lensing was first identified as a phenomenon by Einstein who predicted that light bends around massive objects in space in the same way that light bends going through a lens.

In doing so, it greatly magnifies images of galaxies that we would not otherwise be able to see.

While it has been used by astronomers to observe far away galaxies for a long time, finding these cosmic magnifying glasses in the first place has been hit and miss.

"These lenses are very small so if you have fuzzy images, you're not going to really be able to detect them," says Dr. Tran.

While these lenses let us see objects that are millions of light years away more clearly, it should also let us 'see' invisible dark matter that makes up most of the Universe.

"We know that most of the mass is dark," says Dr. Tran. "We know that mass is bending light and so if we can measure how much light is bent, we can then infer how much mass must be there."

Having many more gravitational lenses at various distances will also give us a more complete image of the timeline going back almost to the Big Bang.

"The more magnifying glasses you have, the better chance you can try to survey these more distant objects. Hopefully, we can better measure the demographics of very young galaxies," says Dr. Tran.

"Then somewhere between those really early first galaxies and us there's a whole lot of evolution that's happening, with tiny star forming regions that convert pristine gas into the first stars to the sun, the Milky Way.

"And so with these lenses at different distances, we can look at different points in the cosmic timeline to track essentially how things change over time, between the very first galaxies and now."

Dr Tran's team spanned the globe, with each group providing different expertise.

"Being able to collaborate with people, at different universities, has been so crucial, both for setting the project up in the first place, and now continuing with all of the follow-up observations," she says.

Professor Stuart Wyithe of the University of Melbourne and Director of the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (Astro 3D) says each gravitational lens is unique and tells us something new.

"Apart from being beautiful objects, gravitational lenses provide a window to studying how mass is distributed in very distant galaxies that are not observable via other techniques. By introducing ways to use these new large data sets of the sky to search for many new gravitational lenses, the team opens up the opportunity to see how galaxies get their mass," he says.

Professor Karl Glazebrook of Swinburne University, and Dr Tran's Co-Science Lead on the paper, paid tribute to the work that had gone before.

"This algorithm was pioneered by Dr Colin Jacobs at Swinburne. He sifted through tens of millions of galaxy images to prune the sample down to 5,000. Never did we dream that the success rate would be so high," he says.

"Now we are getting images of these lenses with the Hubble Space Telescope, they range from jaw-droopingly beautiful to extremely strange images that will take us considerable effort to figure out."

Associate Professor Tucker Jones of UC Davis, another co-science lead on the paper, described the new sample as "a giant step forward in learning how galaxies form over the history of the Universe."

"Normally these early galaxies look like small fuzzy blobs, but the lensing magnification allows us to see their structure with much better resolution. They are ideal targets for our most powerful telescopes to give us the best possible view of the early universe," he says.

"Thanks to the lensing effect we can learn what these primitive galaxies look like, what they are made of, and how they interact with their surroundings."

Read more at Science Daily

Armored worm reveals the ancestry of three major animal groups

An international team of scientists, including from the Universities of Bristol and Oxford, and the Natural History Museum, have discovered that a well-preserved fossilised worm dating from 518 million years ago resembles the ancestor of three major groups of living animals.

Measuring half-an-inch long, the fossil worm -- named Wufengella and unearthed in China -- was a stubby creature covered in a dense, regularly overlapping array of plates on its back, belonging to an extinct group of shelly organisms called tommotiids.

Surrounding the asymmetrical armour was a fleshy body with a series of flattened lobes projecting from the sides. Bundles of bristles emerged from the body in between the lobes and the armour. The many lobes, bundles of bristles and array of shells on the back are evidence that the worm was originally serialised or segmented, like an earthworm.

The findings are reported today in the journal Current Biology. Study co-author, Dr Jakob Vinther from the University of Bristol's School of Earth Sciences, said: "It looks like the unlikely offspring between a bristle worm and a chiton mollusc. Interestingly, it belongs to neither of those groups."

The animal kingdom consists of more than 30 major body plans categorised as phyla. Each phylum harbours a set of features that set them apart from one another. Only a few features are shared across more than one group, which is a testament to the very fast rate of evolution during which these major groups of animals originated, called the Cambrian Explosion, about 550 million years ago.

Brachiopods are a phylum that superficially resemble bivalves (such as clams) in having a pair of shells and living attached to the seafloor, rocks or reefs. However, when looking inside, brachiopods reveal themselves to be very different in many respects. In fact, brachiopods filter water using a pair of tentacles folded up into a horseshoe-shape organ.

Such an organ is called a lophophore and brachiopods share the lophophore with two other major groups called the phoronids ("horseshoe worms") and bryozoans ("moss animals"). Molecular studies -- which reconstruct evolutionary trees using amino acid sequences -- agree with anatomical evidence that brachiopods, bryozoans and phoronids are each other's closest living relatives, a group called Lophophorata after their filter-feeding organ.

Co-author Dr Luke Parry from the University of Oxford added: "Wufengella belongs to a group of Cambrian fossils that's crucial for understanding how lophophorates evolved. They're called tommotiids, and thanks to these fossils we have been able to understand how brachiopods evolved to have two shells from ancestors with many shell-like plates arranged into a cone or tube.

"We have known for a long time about this tommotiid group called camenellans. Palaeontologists have thought that those shells were attached to an agile organism -- crawling around -- rather than being fixed in one place and feeding with a lophophore."

The team, which consists of palaeontologists from the University of Bristol, Yunnan University, the Chengjiang Museum of Natural History, University of Oxford, the Natural History Museum in London and the Muséum national d'Histoire Naturelle in Paris, demonstrate that Wufengella is a complete camenellan tommotiid, which means that reveals what the long sought-after wormy ancestor to lophophorates looked like.

Dr Parry added: "When it first became clear to me what this fossil was that I was looking at under the microscope, I couldn't believe my eyes. This is a fossil that we have often speculated about and hoped we would one day lay eyes on."

While the fossil fulfils the palaeontological prediction that the lophophorates' ancestral lineage was an agile, armoured worm, the appearance of its soft anatomy brings into focus some hypotheses about how lophophorates may be related to segmented worms.

Dr Vinther said: "Biologists had long noted how brachiopods have multiple, paired body cavities, unique kidney structures and bundles of bristles on their back as larvae. These similarities led them to notice how closely brachiopods resemble annelid worms."

"We now can see that those similarities are reflections of shared ancestry. The common ancestor of lophophorates and annelids had an anatomy most closely resembling the annelids.

"At some point, the tommotiid ancestor to the lophophorates became sessile and evolved suspension feeding (catching particles suspended in the water). Then a long, wormy body with numerous, repeated body units became less useful and was reduced."

Co-author Greg Edgecombe from the Natural History Museum said: "This discovery highlights how important fossils can be for reconstructing evolution.

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An ocean inside Earth? Water hundreds of kilometers down

The transition zone (TZ) is the name given to the boundary layer that separates the Earth's upper mantle and the lower mantle. It is located at a depth of 410 to 660 kilometres. The immense pressure of up to 23,000 bar in the TZ causes the olive-green mineral olivine, which constitutes around 70 percent of the Earth's upper mantle and is also called peridot, to alter its crystalline structure. At the upper boundary of the transition zone, at a depth of about 410 kilometres, it is converted into denser wadsleyite; at 520 kilometres it then metamorphoses into even denser ringwoodite.

"These mineral transformations greatly hinder the movements of rock in the mantle," explains Prof. Frank Brenker from the Institute for Geosciences at Goethe University in Frankfurt. For example, mantle plumes -- rising columns of hot rock from the deep mantle -- sometimes stop directly below the transition zone. The movement of mass in the opposite direction also comes to standstill. Brenker says, "Subducting plates often have difficulty in breaking through the entire transition zone. So there is a whole graveyard of such plates in this zone underneath Europe."

However, until now it was not known what the long-term effects of "sucking" material into the transition zone were on its geochemical composition and whether larger quantities of water existed there. Brenker explains: "The subducting slabs also carry deep-sea sediments piggy-back into the Earth's interior. These sediments can hold large quantities of water and CO2. But until now it was unclear just how much enters the transition zone in the form of more stable, hydrous minerals and carbonates -- and it was therefore also unclear whether large quantities of water really are stored there."

The prevailing conditions would certainly be conducive to that. The dense minerals wadsleyite and ringwoodite can (unlike the olivine at lesser depths) store large quantities of water- in fact so large that the transition zone would theoretically be able to absorb six times the amount of water in our oceans. "So we knew that the boundary layer has an enormous capacity for storing water," Brenker says. "However, we didn't know whether it actually did so."

An international study in which the Frankfurt geoscientist was involved has now supplied the answer. The research team analysed a diamond from Botswana, Africa. It was formed at a depth of 660 kilometres, right at the interface between the transition zone and the lower mantle, where ringwoodite is the prevailing mineral. Diamonds from this region are very rare, even among the rare diamonds of super-deep origin, which account for only one percent of diamonds. The analyses revealed that the stone contains numerous ringwoodite inclusions -- which exhibit a high water content. Furthermore, the research group was able to determine the chemical composition of the stone. It was almost exactly the same as that of virtually every fragment of mantle rock found in basalts anywhere in the world. This showed that the diamond definitely came from a normal piece of the Earth's mantle. "In this study we have demonstrated that the transition zone is not a dry sponge, but holds considerable quantities of water," Brenker says, adding: "This also brings us one step closer to Jules Verne's idea of an ocean inside the Earth." The difference is that there is no ocean down there, but hydrous rock which, according to Brenker, would neither feel wet nor drip water.

Hydrous ringwoodite was first detected in a diamond from the transition zone as early as 2014. Brenker was involved in that study, too. However, it was not possible to determine the precise chemical composition of the stone because it was too small. It therefore remained unclear how representative the first study was of the mantle in general, as the water content of that diamond could also have resulted from an exotic chemical environment. By contrast, the inclusions in the 1.5 centimetre diamond from Botswana, which the research team investigated in the present study, were large enough to allow the precise chemical composition to be determined, and this supplied final confirmation of the preliminary results from 2014.

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Ending a 50-year mystery, scientists reveal how bacteria can move

University of Virginia School of Medicine researchers and their collaborators have solved a decades-old mystery about how E. coli and other bacteria are able to move.

Bacteria push themselves forward by coiling long, threadlike appendages into corkscrew shapes that act as makeshift propellers. But how exactly they do this has baffled scientists, because the "propellers" are made of a single protein.

An international team led by UVA's Edward H. Egelman, PhD, a leader in the field of high-tech cryo-electron microscopy (cryo-EM), has cracked the case. The researchers used cryo-EM and advanced computer modeling to reveal what no traditional light microscope could see: the strange structure of these propellers at the level of individual atoms.

"While models have existed for 50 years for how these filaments might form such regular coiled shapes, we have now determined the structure of these filaments in atomic detail," said Egelman, of UVA's Department of Biochemistry and Molecular Genetics. "We can show that these models were wrong, and our new understanding will help pave the way for technologies that could be based upon such miniature propellers."

Blueprints for Bacteria's 'Supercoils'

Different bacteria have one or many appendages known as a flagellum, or, in the plural, flagella. A flagellum is made of thousands of subunits, but all these subunits are exactly the same. You might think that such a tail would be straight, or at best a bit flexible, but that would leave the bacteria unable to move. That's because such shapes can't generate thrust. It takes a rotating, corkscrew-like propeller to push a bacterium forward. Scientists call the formation of this shape "supercoiling," and now, after more than 50 years, they understand how bacteria do it.

Using cryo-EM, Egelman and his team found that the protein that makes up the flagellum can exist in 11 different states. It is the precise mixture of these states that causes the corkscrew shape to form.

It has been known that the propeller in bacteria is quite different than similar propellers used by hearty one-celled organisms called archaea. Archaea are found in some of the most extreme environments on Earth, such as in nearly boiling pools of acid, the very bottom of the ocean and in petroleum deposits deep in the ground.

Egelman and colleagues used cryo-EM to examine the flagella of one form of archaea, Saccharolobus islandicus, and found that the protein forming its flagellum exists in 10 different states. While the details were quite different than what the researchers saw in bacteria, the result was the same, with the filaments forming regular corkscrews. They conclude that this is an example of "convergent evolution" -- when nature arrives at similar solutions via very different means. This shows that even though bacteria and archaea's propellers are similar in form and function, the organisms evolved those traits independently.

"As with birds, bats and bees, which have all independently evolved wings for flying, the evolution of bacteria and archaea has converged on a similar solution for swimming in both," said Egelman, whose prior imaging work saw him inducted into the National Academy of Sciences, one of the highest honors a scientist can receive. "Since these biological structures emerged on Earth billions of years ago, the 50 years that it has taken to understand them may not seem that long."

Read more at Science Daily

Sep 27, 2022

NASA's DART mission hits asteroid in first-ever planetary defense test

After 10 months flying in space, NASA's Double Asteroid Redirection Test (DART) -- the world's first planetary defense technology demonstration -- successfully impacted its asteroid target on Monday, the agency's first attempt to move an asteroid in space.

Mission control at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, announced the successful impact at 7:14 p.m. EDT.

As a part of NASA's overall planetary defense strategy, DART's impact with the asteroid Dimorphos demonstrates a viable mitigation technique for protecting the planet from an Earth-bound asteroid or comet, if one were discovered.

"At its core, DART represents an unprecedented success for planetary defense, but it is also a mission of unity with a real benefit for all humanity," said NASA Administrator Bill Nelson. "As NASA studies the cosmos and our home planet, we're also working to protect that home, and this international collaboration turned science fiction into science fact, demonstrating one way to protect Earth."

DART targeted the asteroid moonlet Dimorphos, a small body just 530 feet (160 meters) in diameter. It orbits a larger, 2,560-foot (780-meter) asteroid called Didymos. Neither asteroid poses a threat to Earth.

The mission's one-way trip confirmed NASA can successfully navigate a spacecraft to intentionally collide with an asteroid to deflect it, a technique known as kinetic impact.

The investigation team will now observe Dimorphos using ground-based telescopes to confirm that DART's impact altered the asteroid's orbit around Didymos. Researchers expect the impact to shorten Dimorphos' orbit by about 1%, or roughly 10 minutes; precisely measuring how much the asteroid was deflected is one of the primary purposes of the full-scale test.

"Planetary Defense is a globally unifying effort that affects everyone living on Earth," said Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington. "Now we know we can aim a spacecraft with the precision needed to impact even a small body in space. Just a small change in its speed is all we need to make a significant difference in the path an asteroid travels."

The spacecraft's sole instrument, the Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO), together with a sophisticated guidance, navigation and control system that works in tandem with Small-body Maneuvering Autonomous Real Time Navigation (SMART Nav) algorithms, enabled DART to identify and distinguish between the two asteroids, targeting the smaller body.

These systems guided the 1,260-pound (570-kilogram) box-shaped spacecraft through the final 56,000 miles (90,000 kilometers) of space into Dimorphos, intentionally crashing into it at roughly 14,000 miles (22,530 kilometers) per hour to slightly slow the asteroid's orbital speed. DRACO's final images, obtained by the spacecraft seconds before impact, revealed the surface of Dimorphos in close-up detail.

Fifteen days before impact, DART's CubeSat companion Light Italian CubeSat for Imaging of Asteroids (LICIACube), provided by the Italian Space Agency, deployed from the spacecraft to capture images of DART's impact and of the asteroid's resulting cloud of ejected matter. In tandem with the images returned by DRACO, LICIACube's images are intended to provide a view of the collision's effects to help researchers better characterize the effectiveness of kinetic impact in deflecting an asteroid. Because LICIACube doesn't carry a large antenna, images will be downlinked to Earth one by one in the coming weeks.

"DART's success provides a significant addition to the essential toolbox we must have to protect Earth from a devastating impact by an asteroid," said Lindley Johnson, NASA's Planetary Defense Officer. "This demonstrates we are no longer powerless to prevent this type of natural disaster. Coupled with enhanced capabilities to accelerate finding the remaining hazardous asteroid population by our next Planetary Defense mission, the Near-Earth Object (NEO) Surveyor, a DART successor could provide what we need to save the day."

With the asteroid pair within 7 million miles (11 million kilometers) of Earth, a global team is using dozens of telescopes stationed around the world and in space to observe the asteroid system. Over the coming weeks, they will characterize the ejecta produced and precisely measure Dimorphos' orbital change to determine how effectively DART deflected the asteroid. The results will help validate and improve scientific computer models critical to predicting the effectiveness of this technique as a reliable method for asteroid deflection.

"This first-of-its-kind mission required incredible preparation and precision, and the team exceeded expectations on all counts," said APL Director Ralph Semmel. "Beyond the truly exciting success of the technology demonstration, capabilities based on DART could one day be used to change the course of an asteroid to protect our planet and preserve life on Earth as we know it."

Read more at Science Daily

Among ancient Mayas, cacao was not a food exclusive to the elite

It was the money that grew on trees.

Said to be a gift from the gods, cacao for the ancient Maya was considered sacred, used not only as currency, but in special ceremonies and religious rituals. It's the progenitor plant of chocolate, and notions of luxury are embedded in its lore.

The prevailing belief: Cacao was more available to, even controlled by, the society's very upper echelons, royalty. Past efforts to identify cacao in ceramics focused on highly decorative vessels associated with elite ceremonial contexts -- think ornate drinking vases -- leading to assumptions about how cacao was distributed and who could access it.

What about the farmers who grew cacao and the communities of people who lived amongst these orchards? What of the general populace?

A new study by UC Santa Barbara researchers Anabel Ford and Mattanjah de Vries asks these questions -- and answers them -- by examining cacao residues from ancient ceramics. Their results, published in the Proceedings of the National Academy of Sciences, demonstrate that cacao was, in fact, accessible to the general populace and was used in celebrations at all levels of society.

"It had long been assumed that cacao for the Maya was an elite exclusive," said Ford, an anthropologist and director of the MesoAmerican Research Center at UC Santa Barbara, who for 40 years has been conducting research on the ancient Maya city of El Pilar. "We now know this is not the case. The imbibing of cacao was a luxury accessible to all. The importance is that it was a requirement of the rituals associated with it."

To test the exclusivity of cacao use, the work examines 54 archaeological ceramic sherds. Originating from El Pilar -- located between Belize and Guatemala -- the sherds can be traced to Late Classic period civic and residential contexts, representing a cross section of ancient Maya inhabitants. The study includes a chemical analysis of these sherds -- specifically of the biomarkers for cacao: caffeine, theobromine and theophylline.

"The discovery of chemical signatures of cacao made the investigation possible, but the main active ingredient, theobromine, it turns out is not sufficiently discrete to be certain of the cacao attribution," said Ford. "Mattanjah (de Vries) and his students, in their chemical research, encountered the possibility of detecting theophylline, a specific component of cacao that could not be confused with anything else. His work was not archaeological, but he saw the potential for an interdisciplinary project."

A distinguished professor and department chair of chemistry and biochemistry at UC Santa Barbara, de Vries has long been studying how DNA bases -- the building blocks of life -- and similar molecules respond to UV light and, he said, whether UV light "could have played a role on an early Earth, in the way nature selected those building blocks from a primordial soup of many such compounds.

"At some point I realized that some of the compounds we had been studying in this origin of life chemistry project occur in cacao, and thus can serve as biomarkers for cacao," de Vries said. "Since we had already investigated the spectroscopy of these compounds in great detail, this presented an opportunity to apply that expertise to detection of these biomarkers for archaeology.

"We can find a needle in a haystack, provided we know what the needle looks like; in this case the target molecule was a certain biomarker for cacao," he added. "That ability is what made this analysis possible."

In their selection of ceramics to test, Ford and de Vries prioritized the vases from which cacao was likely drunk. They also tested bowls, jars and plates. All vessel types had evidence of cacao.

"This was a surprise at first," Ford said, "but giving thought to the presence and understanding of their uses, bowls would be good for mixing, jars would be right for warming the drink (a traditional cacao preparation) and plates appropriate for serving food with sauces that can contain cacao (such as mole poblano).

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Key phases of human evolution coincide with flickers in eastern Africa's climate

Three distinct phases of climate variability in eastern Africa coincided with shifts in hominin evolution and dispersal over the last 620,000 years, an analysis of environmental proxies from a lake sediment record has revealed. The project explores the youngest chapter in human evolution by analysing lacustrine sediments in close vicinity to paleo-anthropological key sites in eastern Africa using scientific deep drilling. The research endeavour included more than 22 researchers from 19 institutions in 6 countries, and was led by Dr Verena Foerster at the University of Cologne's Institute of Geography Education. The article 'Pleistocene climate variability in eastern Africa influenced hominin evolution' has now appeared in Nature Geoscience.

Despite more than half a century of hominin fossil discoveries in eastern Africa, the regional environmental context of the evolution and dispersal of modern humans and their ancestors is not well established. Particularly for the Pleistocene (or Ice Age) between 2,580,000 to 11,700 years ago, there are no continuous high-resolution paleo-environmental records available for the African continent.

The research team extracted two continuous 280-metre sediment cores from the Chew Bahir Basin in southern Ethiopia, an area where early humans lived and developed during the Pleistocene. Chew Bahir is very remotely situated in a deep tectonic basement in close vicinity to the Turkana area and the Omo-Kibish, key paleo-anthropological and archaeological sites. The cores yielded the most complete record for such a long period ever extracted in the area, revealing how different climates influenced the biological and cultural transformation of humans inhabiting the region.

An interdisciplinary team including geoscientists, sedimentologists, micro-paleontologists, geologists, geographers, geochemists, archaeologists, chronologists, and climate modellers worked towards recovering the two continuous sediment cores, from which so-called proxies (like microfossils or elemental variations) were used to glean data to reconstruct the region's climate history. Archaeologists, evolutionary biologists, and evolutionary anthropologists then identified phases of climatic stress as well as more favourable conditions and interpreted how these factors changed human habitats, influencing human biological and cultural evolution as well as their dispersal.

Specifically, the scientists found that various anatomically diverse hominin groups inhabited the area during a phase of long-lasting and relatively stable humid conditions from approximately 620,000 to 275,000 years BP (Before Present). However, a series of shorter abrupt and extreme arid pulses interrupted this long generally stable and wet phase. Most likely, this resulted in a fragmentation of habitats, shifts in population dynamics and even the extinctions of local populations. As a result, small, reproductively and culturally isolated populations then had to adapt to dramatically transformed local environments, likely stimulating the appearance of the many geographically and anatomically distinct hominin groups and the separation of our modern human ancestors from archaic groups.

A phase with significant climate swings resulting in regularly transformed habitats in the area from approximately 275,000 to 60,000 years BP repeatedly resulted in environmental shifts from lush vegetation with deep fresh water lakes to highly arid landscapes with the extensive lakes reduced to small saline puddles. In this phase, the population groups gradually transitioned from Acheulean technologies (oval hand axes made of stone and primarily associated with Homo ergaster/erectus) to more sophisticated Middle Stone Age technologies. This crucial phase also encompasses the emergence of Homo sapiens in eastern Africa as well as key human social, technological, and cultural innovations that could have buffered early Homo sapiens from the impacts of severe environmental changes. 'These innovations, such as more varied toolkits and long-distance transport, would have equipped modern humans with an unprecedented adaptability to the repeated expansions and contractions of habitats,' said Dr Foerster, the paper's lead author.

The phase from approximately 60,000 to 10,000 years BP saw the most extreme environmental fluctuations, but also the most arid phase of the entire record, which could have acted as a motor for continuous indigenous cultural change. The scientists believe that the brief alignment of humid pulses in eastern Africa with wet phases in north-eastern Africa and the Mediterranean was key to opening favourable migration routes out of Africa on a roughly north-south axis along the East African Rift System (EARS) and into the Levant, facilitating the global dispersal of Homo sapiens.

'In view of current threats to the human habitat from climate change and the overuse of natural resources through human activity, understanding how the relationship between climate and human evolution has become more relevant than ever,' Foerster concluded.

This research is part of the Hominin Sites and Paleolakes Drilling Project (HSPDP). In order to evaluate the impact that different timescales and magnitudes of climatic shifts have had on the living conditions of early humans, the project has cored five lake archives of climate change during the last 3.5 million years. All five sites in Kenya and Ethiopia are located in close vicinity to paleoanthropological key sites covering various steps in human evolution, with the site in southern Ethiopia exploring the youngest chapter.

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Study finds all African carnivores at risk for range loss

A new Yale School of the Environment-led analysis identifying gaps in maps that help forecast range contractions for African species found that all species studied have a portion of their range at risk and small carnivores warrant more concern.

The study, published in PNAS and led by YSE Knobloch Family Associate Professor of Wildlife and Land Conservation Nyeema C. Harris, assessed 91 African carnivores to identify gaps in capacity necessary for their conservation.

Harris's team found that contrary to current perceptions, many species that are currently classified as "least concern" on the International Union for the Conservation of Nature Red List of Threatened Species had high percentages of their range at risk of contraction. For example, the common slender mongoose (Herpestes sanguineus) and serval (Leptailurus serval) both have 16% of their ranges at risk of contraction while it was 70% for the Egyptian weasel (Mustela subpalmata). Harris says the most important finding of the study, which analyzed additional data not previously assessed, is that all species studied have some portion of their range at risk of contraction due to burgeoning threats, with an average of 15% of African carnivore ranges at-risk.

"There's a growing interest in relying on geospatial data to make conservation decisions but the range maps are flawed," says Harris. "Traditional gap analyses do not consider both threats and assets across the range that influence population persistence. We are introducing a novel approach by assessing these different variables."

Most surprising, she says, is the amount of contractions and variations in ranges of species the team's model was able to determine. The study reported that some large carnivores that are classified as endangered by the IUCN Red list, including the Ethiopian wolf (Canis simensis) and the African wild dog (Lycaon pictus), had 33% and 3% of range at risk of contraction, respectively.

"We were able to get new insights about species that are largely unknown or understudied, and we identified that there are some conservation concerns because they have very small ranges comprised of more threats than assets," says Harris. "The model is giving us a broader understanding and a different approach to anticipating biodiversity losses, especially for species with limited information classified as 'data deficient' by the IUCN Redlist, such as the Ethiopian Genet (Genetta abyssinica, a catlike mammal) and Pousargues's mongoose (Dologale dybowskii), also known as African tropical savannah mongoose."

Africa contains a third of the world's carnivore species that persist in a landscape fraught with anthropogenic and environmental pressures, as well as rich biocultural diversity. The study examines possible assets to conservation, such as distribution of Indigenous lands and cultural diversity, and threats to carnivores, such as drought risks and exposure to urbanization or agriculture.

It highlights some anthropic factors that are helping conservation efforts. For example, customary laws and traditional ceremonies of the Nharira community in central Zimbabwe include biodiversity protection.

"The blanket inclusion of human density as inherently and exclusively an environmental stressor is not accurate," the authors note. "By seeking, incorporating, and respecting traditional ecological knowledge of people in places, conservation can progress to a more inclusive practice and promote species ranges under varying global change scenarios."

Harris says more work needs to be done to fill out the full extent of variables distributed across species ranges -- an idea she calls textured range maps. She notes that such efforts can complement existing frameworks such as the IUCN Red List.

She says their model will be used for a global carnivore assessment, and she hopes other researchers will apply similar approaches to study different groups of conservation interests, such as primate and amphibians around the world.

"It will allow us to set a very explicit agenda around conservation strategy," she says.

The study was co-authored by YSE doctoral student Siria Gámez; Asia Murphy, postdoctoral fellow at the Department of Environmental Studies, University of California, Santa Cruz; Aalayna R. Green, doctoral student in natural resources at Cornell University; Daniel M. Mwamidi, doctoral student at the Institution of Environmental Science and Technology at the Autonomous University of Barcelona; and Gabriela C. Nunez-Mir, assistant professor of biological sciences at the University of Illinois, Chicago.

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Sep 26, 2022

How global warming affects astronomical observations

The quality of ground-based astronomical observations delicately depends on the clarity of the atmosphere above the location from which they are made. Sites for telescopes are therefore very carefully selected. They are often high above sea level, so that less atmosphere stands between them and their targets. Many telescopes are also built in deserts, as clouds and even water vapour hinder a clear view of the night sky.

A team of researchers led by the University of Bern and the National Centre of Competence in Research (NCCR) PlanetS shows in a study, published in the journal Astronomy & Astrophysics and presented at the Europlanet Science Congress 2022 in Granada, how one of the major challenges of our time -- anthropogenic climate change -- now even affects our view of the cosmos.

A blind spot in the selection process

"Even though telescopes usually have a lifetime of several decades, site selection processes only consider the atmospheric conditions over a short timeframe. Usually over the past five years -- too short to capture long-term trends, let alone future changes caused by global warming," Caroline Haslebacher, lead author of the study and researcher at the NCCR PlanetS at the University of Bern, points out. The team of researchers from the University of Bern and the NCCR PlanetS, ETH Zurich, the European Southern Observatory (ESO) as well as the University of Reading in the UK therefore took it upon themselves to show the long-term perspective.

Worsening conditions around the globe


Their analysis of future climate trends, based on high resolution global climate models, shows that major astronomical observatories from Hawaii to the Canary Islands, Chile, Mexico, South Africa and Australia will likely experience an increase in temperature and atmospheric water content by 2050. This, in turn, could mean a loss in observing time as well as a loss of quality in the observations.

"Nowadays, astronomical observatories are designed to work under the current site conditions and only have a few possibilities for adaptation. Potential consequences of the climatic conditions for telescopes therefore include a higher risk of condensation due to an increased dew point or malfunctioning cooling systems, which can lead to more air turbulence in the telescope dome," Haslebacher says.

The fact that the effects of climate change on observatories had not been taken into account before was not an oversight, as study co-author Marie-Estelle Demory says, but was not least due to the state of the art: "This is the first time that such a study has been possible. Thanks to the higher resolution of the global climate models developed through the Horizon 2020 PRIMAVERA project, we were able to examine the conditions at various locations of the globe with great fidelity -- something that we were unable to do with conventional models. These models are valuable tools for the work we do at the Wyss Academy," says the senior scientist at the University of Bern and member of the Wyss Academy for Nature.

"This now allows us to say with certainty that anthropogenic climate change must be taken into account in the site selection for next-generation telescopes, and in the construction and maintenance of astronomical facilities," says Haslebacher.

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Scientists find evidence for food insecurity driving international conflict two thousand years ago

Ancient Palmyra has gripped public imagination since its picturesque ruins were "rediscovered" in the seventeenth century by western travellers. The most legendary story of ancient Palmyra is that of Queen Zenobia ruling over a thriving city in the Syrian Desert who dared to challenge the Roman Empire but ultimately got defeated. Her kingdom was subjugated, and the city was reduced to a small settlement without any wide-ranging importance. This has only recently been overshadowed by the catastrophic events of the Syrian Civil War that saw the archaeological site and the museum plundered and many monuments destroyed.

Deteriorating climate and a growing population

Now, scientists from Aarhus University and the University of Bergen are questioning the historical narrative about the final blow given to the city solely by the Roman invasion in 272/273 CE.

"We can now see that food security, always the main concern for a large urban centre situated in a highly inhospitable environment, was gradually reduced with a deteriorating climate and a growing population of the city. The timing of this nexus matches exactly the time of the reign of Zenobia and of that of her husband, Odaenathus, marked by social shifts, militarisation, the rapid conquest of neighbouring lands and the dramatic conflict that led to the demise of Palmyra," says Dr Iza Romanowska, one of the authors behind the new study.

Interdisciplinary team effort unlocks complex data

The interdisciplinary research team reconstructed the hinterland of ancient Palmyra -- the area around the city that could provide it with basic foodstuff -- and used modern land-use models developed for dry and semi-dry environments to estimate the maximum productivity of the land. They then ran the model against existing climate records to determine how much food could be produced at different points in Palmyra's history and with what reliability. In order to do this, archaeologists, ancient historians and complexity scientists joined forces to unleash the knowledge locked in the otherwise impenetrable data. The results showed that a long-term climatic shift towards drier and hotter climate caused a gradual decrease in agricultural yields, reaching levels barely sufficient to feed the budding population of Palmyra around the middle of the third century.

Innovative new approach -- new angles

Co-author Professor Rubina Raja, Aarhus University's chair of classical archaeology and director of the DNRF-funded Centre of Excellence for Urban Network Evolutions (UrbNet) heads the Carlsberg Foundation-funded project "Circular Economy and Urban Sustainability in Antiquity" from which the study stems. Rubina Raja adds:

"While there have been numerous studies looking at Palmyra's history, social composition and infrastructure, it is thanks to the innovative new approach that we are able to look at the history of this important city and the whole region from an entirely new angle. By combining computational modelling with a wide range of archaeological data processed by humanities researchers with deep historical knowledge we are able to consider the circular economy and its long-term sustainability and resilience."

Learning from the past is key

The study sets up a research pipeline, including computer scripts and detailed instructions, that will enable other researchers to analyse other ancient cities and determine how often and under what circumstances food security played a key role in shaping historical trajectories of past peoples.

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Scientists chart 45 million years of Antarctic temperature change

Molecular fossils and machine learning have enabled scientists to build the first charts of Antarctic ocean temperatures over the past 45 million years, offering important insights into future sea level changes.

The team, led by scientists from Victoria University of Wellington (NZ) and Birmingham (UK) say their results suggest we are nearing a 'tipping point' where ocean warming caused by atmospheric CO2 will cause catastrophic rises in sea levels because of melting ice sheets. Their results are published today (15 September 2022) in Nature Geoscience.

In the study, the team examined molecular fossils from core samples taken during ocean drilling projects. The fossil remains are in fact single lipid (insoluble in water) molecules produced by archaea -- single-celled organisms which are similar to bacteria. The archaea adjust the composition of their outer membrane lipids in response to changing sea temperatures. By studying these changes, scientists can draw conclusions about the ancient sea temperature which would have surrounded a particular sample as it died.

While these molecular fossil techniques are well used by palaeoclimatologists, the team from Wellington (NZ) and Birmingham (UK) went a step further. They used machine learning to refine the technique, giving the first record to date of changing Antarctic sea temperatures throughout much of the Cenozoic period -- covering the past 45 million years.

That means scientists are able to pinpoint much more accurately the historic temperatures which caused ice sheets to grow and shrink during that period. The future loss of ice sheets and the retreat of glaciers in the Antarctic is critically important as melting ice in the region could sea levels to rise by up to 50 m.

"The record we've produced offers a much more robust overview of fluctuating Antarctic temperatures and how these relate to changes in the amount of ice, and the topography of Antarctica, over this period and paves the way for improved estimates of future events," explains the Birmingham lead author Dr James Bendle.

The link between CO2, sea-surface temperatures and the amount of ice on Antarctica is clear through the last 45 million years. But one surprising finding was that ocean cooling did not always correspond to increases in Antarctic ice. Specifically for a 1 million year long period of ocean cooling from 25 to 24 million years ago. "We show that this is likely related to tectonic subsidence and the influx of relatively warm ocean water in the Ross Sea region," says Dr Bendle.

"We can see that ice in Antarctica is currently changing -- not least with the loss of some ice-shelves and cracks appearing recently in the Thwaites Glacier, one of the largest glaciers in the region. This new study of Earth's past is one of the clearest indications yet that humans continue to produce CO2 levels for which we can expect major ice loss at the Antarctic margins and global sea-level rise over the coming decades and centuries."

The team plan to continue to apply biomarker and machine learning approaches to reconstruct the climatic evolution of Antarctica and implications for future warming and sea-level rise.

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Longhorned tick discovered in northern Missouri

The Longhorned tick causes the loss of millions of dollars in agricultural revenue to cattle producers worldwide, and it is now in northern Missouri.

Originally found in eastern Russia and the Australasian region, this tick was first found in the United States in 2017 in New Jersey. It has since reached the Mid-Atlantic, New England and Midwestern regions of the U.S., and now has been discovered in northern Missouri for the first time by researchers at the University of Missouri.

Last year, the Longhorned tick was found in the southern part of the state. This latest discovery indicates an additional economic burden to cattle producers due to ticks; as the Longhorned tick infestation could lead to significant loss in weight gain for cattle, similar to an already widely prevalent disease called anaplasmosis; but so far, the threat from this species of tick to cattle -- and people and their pets -- in Missouri remains low. However, researchers emphasize that the discovery of the Longhorned tick in the state increases the need for more vigilance towards ticks in general.

While most ticks reproduce traditionally, female Longhorned ticks can lay thousands of eggs without the help of a male, which makes it easier for them to quickly establish in new areas. Infestation of the Longhorned tick can lead to possible transmission of bovine theileriosis, a disease that kills red blood cells in cattle.

While there have currently not been any confirmed cases of bovine theileriosis in Missouri cattle, this discovery further heightens the need for Missouri cattle ranchers to make informed decisions regarding quarantining protocols when introducing new cattle into their herds in an effort to protect the health of their livestock, which has significant economic implications.

"Studying the prevalence of invasive ticks in different geographical regions can help veterinarians and farmers take proactive, preventative steps that may ultimately protect the health of livestock, which has huge economic implications," said Rosalie Ierardi, an anatomic pathologist at the MU College of Veterinary Medicine who recently discovered two Longhorned ticks in Linn County, Missouri, while conducting anaplasmosis surveillance research.

Ierardi collaborated on the project with Ram Raghavan, a professor in the MU College of Veterinary Medicine and MU School of Health Professions. Raghavan, who has been tracking the spread of various species of ticks in the U.S. for 15 years, predicted the potential geographic distribution of the Longhorned tick back in 2019. So far, the tick appears to be establishing in the areas that he had predicted in that study. He said there not only appears to be an increase in the abundance of all ticks in the Midwest in the past decade, but also an increase in the pathogens and diseases they transmit to cattle, humans and pets.

"Warmer temperatures in the Midwest seem to be creating perfect conditions for ticks and the pathogens they carry to thrive, and this problem may get worse going forward as the planet continues to warm, which is concerning," Raghavan said. "We must be vigilant and devote resources toward trying to prevent these ticks from spreading diseases that harm the health of cattle, humans and their pets. The discovery of Longhorned ticks in northern Missouri greatly increases the need for more vigilance towards ticks in general and the need for routine monitoring of the pathogens they transmit."

Ierardi encourages cattle ranchers who notice weakness, jaundice and pregnancy loss in their cattle to contact their local veterinarian and the MU Veterinary Medical Diagnostic Laboratory for assistance with tracking down the causes for such signs.

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