Thursday, December 17, 2020

#SPACERACE2.0
Moon rocks in hand, China prepares for future moon missions
By SAM McNEIL, Associated Press
Published: December 17, 2020
A model of China's Chang'e 5 lunar orbiter and lander are displayed before a press conference at the State Council Information Office in Beijing, Thursday, Dec. 17, 2020. Following the successful return of moon rocks by its Chang'e 5 robotic probe, China is preparing for future missions that could set the stage for an eventual lunar base to host human explorers. (AP Photo/Mark Schiefelbein) Photo Gallery Moon rocks in hand, China prepares for future moon missions - Columbian.com


BEIJING — Following the successful return of moon rocks by its Chang’e 5 robotic probe, China is preparing for future missions that could set the stage for an eventual lunar base to host human explorers, a top space program official said Thursday.

China’s next three lunar missions are on track, along with programs for returning samples from Mars and exploring asteroids and the planet Jupiter, Deputy Chief Commander of the China Lunar Exploration Program Wu Yanhua said.

“Exploring the truth of the universe is just beginning,” Wu said at a news conference held hours after the Chang’e 5?s capsule parachuted to a landing in Inner Mongolia carrying the first lunar samples to be brought to Earth in more than 40 years.

Named after the Chinese goddess of the moon, the Chang’e program has made three landings there, including on its less explored far side. Chang’e 6, scheduled for a 2023 launch, is to collect more samples from the lunar south pole, while its two successors are to conduct detailed surveys and test technologies needed for the construction of a science base on the moon.

No dates have been given for Chang’e 7 and 8, or for a crewed mission to the moon that China says is in the works, or for the construction of a lunar base.

“China is willing to keep on contributing to the world and enhancing human well-being with Chinese space solutions,” Wu said.

The capsule of the Chang’e 5 probe and its cargo of samples were flown to the space program’s Beijing campus after landing just before 2 a.m. on Thursday.

The mission achieved firsts for China’s lunar exploration program in collecting samples, launching a vehicle from the moon’s surface and docking it with the capsule to transfer the samples for their voyage to Earth, the China National Space Administration said in a statement issued following the landing.

“As our nation’s most complex and technically groundbreaking space mission, Chang’e 5 has achieved multiple technical breakthroughs … and represents a landmark achievement,” it said.

China in 2003 became just the third country to send an astronaut into orbit on its own after the Soviet Union and the United States and its space program has proceeded along a steady, cautious track, largely avoiding the fatalities and launch failures that marred the U.S.-Soviet space race of the 1960s.

Wu said the latest flight featured collaboration with the European Space Agency, along with Argentina, Namibia, Pakistan and other nations with which Chinese cooperates on monitoring and communicating with its spacecraft. China in the future will “encourage more scientists around the world to participate to obtain more scientific results,” Wu said.

One exception remains the United States. Amid concerns over the Chinese space program’s secrecy and close military connections, American law forbids cooperation between NASA and the CNSA unless Congress gives its approval. That has prevented China from taking part in the International Space Station and helped drive Beijing to launch a now-defunct experimental space station and formulate plans to complete a permanent orbiting outpost within the next two years.

Two of Chang’e 5’s four modules set down on the moon on Dec. 1 and collected about 2 kilograms (4.4 pounds) of samples by scooping them from the surface and drilling 2 meters (about 6 feet) into the moon’s crust. The samples were deposited in a sealed container that was carried back to the return module by an ascent vehicle.

The newly collected rocks are thought to be billions of years younger than those obtained earlier by the U.S. and former Soviet Union, offering new insights into the history of the moon and other bodies in the solar system. They come from a part of the moon known as the Oceanus Procellarum, or Ocean of Storms, near a site called the Mons Rumker that was believed to have been volcanic in ancient times.

As with the 382 kilograms (842 pounds) of lunar samples brought back by U.S. astronauts from 1969 to 1972, they will be analyzed for age and composition and are expected to be shared with other countries.

The age of the samples will help fill in a gap in knowledge about the history of the moon between roughly 1 billion and 3 billion years ago, Brad Jolliff, director of the McDonnell Center for the Space Sciences at Washington University in the U.S. city of St. Louis, wrote in an email. They may also yield clues as to the availability of economically useful resources on the moon such as concentrated hydrogen and oxygen, Jolliff said.

“These samples will be a treasure trove!” Jolliff wrote. “My hat is off to our Chinese colleagues for pulling off a very difficult mission; the science that will flow from analysis of the returned samples will be a legacy that will last for many, many years, and hopefully will involve the international community of scientists.”

Whether U.S. researchers will have access to the samples depends on American policy, Wu said.

“Regardless of whether they are American government departments, commercial operations, scientists or engineers, we sincerely seek friendly cooperation on the basis of equality, mutual benefit and peaceful application,” Wu said.

#SPACERACE2.0

UPDATED 

China moon probe Chang'e-5 lands back on Earth


Researchers work around Chang'e-5 carrying moon samples next to a Chinese national flag in Siziwang. Reuters

Gulf Today Report

China's Chang'e-5 moon probe has landed in the northern Chinese region of Inner Mongolia, with the first fresh samples of rock and debris from the moon in more than 40 years.

The official Xinhua news agency reported that the capsule of the Chang’e 5 probe landed just before 2am (1800 GMT Wednesday) in the Siziwang district of the Inner Mongolia region.

The state media also said the capsule earlier separated from its orbiter module and performed a bounce off Earth’s atmosphere to reduce its speed before passing through and floating to the ground on parachutes.

Two of the Chang’e 5’s four modules set down on the moon on Dec.1 and collected about 2 kilogrammes (4.4 pounds) of samples by scooping them from the surface and drilling 2 metres (about 6 feet) into the moon’s crust. The samples were deposited in a sealed container that was carried back to the return module by an ascent vehicle.


Recovery crew members film the capsule of the Chang'e 5 probe after it successfully landed in Siziwang district. AP

The successful mission was the latest breakthrough for China’s increasingly ambitious space programme that includes a robotic mission to Mars and plans for a permanent orbiting space station.

Chinese leader Xi Jinping, in a statement read out at the Beijing Aerospace Control Center, called it a major achievement that marked a great step forward for China's space industry, state-run Xinhua News Agency said.

He expressed hope that mission participants would continue to contribute toward building China into a major space power and national rejuvenation, the agency reported.

Recovery crews had prepared helicopters and off-road vehicles to home in on signals emitted by the lunar spacecraft and locate it in the darkness shrouding the vast snow-covered region in China's far north, long used as a landing site for China’s Shenzhou crewed spaceships.


Recovery crew members check on the capsule of the Chang'e 5 probe after its successful landing in Siziwang district. AP

The spacecraft’s return marked the first time scientists have obtained fresh samples of lunar rocks since the former Soviet Union’s Luna 24 robot probe in 1976.

The newly collected rocks are thought to be billions of years younger than those obtained earlier by the US and former Soviet Union, offering new insights into the history of the moon and other bodies in the solar system. They come from a part of the moon known as the Oceanus Procellarum, or Ocean of Storms, near a site called the Mons Rumker that was believed to have been volcanic in ancient times.

As with the 382 kilograms (842 pounds) of lunar samples brought back by US astronauts from 1969 to 1972, they will be analyzed for age and composition and are expected to be shared with other countries.

The age of the samples will help fill in a gap in knowledge about the history of the moon between roughly 1 billion and three billion years ago, Brad Jolliff, director of the McDonnell Center for the Space Sciences at Washington University in the US city of St. Louis, wrote in an email. They may also yield clues as to the availability of economically useful resources on the moon such as concentrated hydrogen and oxygen, Jolliff said.

A researcher works next to Chang'e-5 lunar return capsule carrying moon samples in Siziwang district. Reuters

“These samples will be a treasure trove!” Jolliff wrote. “My hat is off to our Chinese colleagues for pulling off a very difficult mission; the science that will flow from analysis of the returned samples will be a legacy that will last for many, many years, and hopefully will involve the international community of scientists.”

Chang’e 5 blasted off from a launch base in China’s southern island province of Hainan on Nov. 23 and appeared to have completed its highly technically sophisticated mission without a hitch.

It marked China’s third successful lunar landing but the only one to lift off again from the moon. Its predecessor, Chang’e 4, became the first probe to land on the moon’s little-explored far side and continues to send back data on conditions that could affect a future extended stay by humans on the moon.

A Chinese Probe Just Brought Back The First New Samples From The Moon in Decades


(New China TV/YouTube)
SPACE

AFP
16 DECEMBER 2020

An unmanned Chinese spacecraft carrying rocks and soil from the Moon returned safely to Earth early Thursday in the first mission in four decades to collect lunar samples, the Xinhua news agency said.

The return module of the space probe known as Chang'e-5 landed in northern China's Inner Mongolia region, Xinhua said, quoting the China National Space Administration.

Beijing is looking to catch up with the US and Russia after taking decades to match its rivals' achievements and has poured billions into its military-run space programme.

The spacecraft, named after a mythical Chinese Moon goddess, landed on the Moon on December 1 and began its return voyage two days later. While on the Moon it raised the Chinese flag, China's space agency has said.

Scientists hope the samples will help them learn about the Moon's origins, formation and volcanic activity on its surface.

With this mission, China became only the third country to have retrieved samples from the Moon, following the United States and the Soviet Union in the 1960s and 1970s.

This was the first such attempt since the Soviet Union's Luna 24 mission in 1976.

The spacecraft's mission was to collect two kilograms (4.5 pounds) of material in an area known as Oceanus Procellarum – or "Ocean of Storms" – a vast, previously unexplored lava plain, according to the science journal Nature.

Under President Xi Jinping, plans for China's "space dream", as he calls it, have been put into overdrive.

China hopes to have a crewed space station by 2022 and eventually send humans to the Moon.

© Agence France-Presse

Oral contraceptive pills protect against ovarian and endometrial cancer

by Uppsala University
Credit: CC0 Public Domain

A comprehensive study from Uppsala University involving more than 250,000 women shows that oral contraceptive use protects against ovarian and endometrial cancer. The protective effect remains for several decades after discontinuing the use. The study is published in the journal Cancer Research.

Ovarian and endometrial cancer are among the most common gynecological cancers, with a lifetime risk of just over 2%. Endometrial cancer is slightly more common but as it has clearer symptoms and is therefore often detected at an early stage, the mortality rate is low. However, ovarian cancer is among the deadliest cancers, since it is often not detected until it has already spread to other parts of the body.

The first oral contraceptive pill was approved already in the 1960s, and 80% of all women in Western Europe have used oral contraceptives at some point in their life. Oral contraceptives include estrogen and progestin, which are synthetic forms of the female sex hormones. The estrogen and progestin in oral contraceptives prevent ovulation and thereby protect against pregnancy.

In the current study, the scientists compared the incidence of breast, ovarian and endometrial cancers between women that had used oral contraceptive pills and never users.

"It was clear that women who had used oral contraceptive pills had a much lower risk of developing both ovarian and endometrial cancer. Fifteen years after discontinuing with oral contraceptives, the risk was about 50% lower. However, a decreased risk was still detected up to 30-35 years after discontinuation," says Åsa Johansson at the Department of Immunology, Genetics and Pathology, Uppsala University, one of the leading researchers behind the study.

However, oral contraceptive pills have previously been associated with an increased risk of breast cancer.

"Surprisingly, we only found a small increased risk of breast cancer among oral contraceptive users, and the increased risk disappeared within a few years after discontinuation," says Johansson. "Our results suggest that the lifetime risk of breast cancer might not differ between ever and never users, even if there is an increased short-term risk."

The results from the current study are important, since oral contraceptive use has commonly been associated with side effects such as deep vein thrombosis and breast cancer.

"In addition to protecting against pregnancy, we have shown that oral contraceptive pills also have other positive effects. Our results can enable women and physicians to make more informed decisions about which women should use oral contraceptive pills," says Therese Johansson, one of the Ph.D. students behind the study.

Explore further 

More information: Karlsson T, Johansson T, Höglund T, Ek W, Johansson Å. (2020) 
Time-dependent effects of oral contraceptive use on breast, ovarian and endometrial cancers.Cancer Research (2020). 

Journal information: Cancer Research


Provided by Uppsala University
Research strongly suggests COVID-19 virus enters the brain

by Bobbi Nodell, University of Washington
DECEMBER 17, 2020
The S1 protein likely causes the brain to release inflammatory products causing a storm in the brain, researchers said. Credit: Alice Gray

More and more evidence is coming out that people with COVID-19 are suffering from cognitive effects, such as brain fog and fatigue.

And researchers are discovering why. The SARS-CoV-2 virus, like many viruses before it, is bad news for the brain. In a study published Dec.16 in Nature Neuroscience, researchers found that the spike protein, often depicted as the red arms of the virus, can cross the blood-brain barrier in mice.

This strongly suggests that SARS-CoV-2, the cause of COVID-19, can enter the brain.

The spike protein, often called the S1 protein, dictates which cells the virus can enter. Usually, the virus does the same thing as its binding protein, said lead author William A. Banks, a professor of medicine at the University of Washington School of Medicine and a Puget Sound Veterans Affairs Healthcare System physician and researcher. Banks said binding proteins like S1 usually by themselves cause damage as they detach from the virus and cause inflammation.

"The S1 protein likely causes the brain to release cytokines and inflammatory products," he said.

In science circles, the intense inflammation caused by the COVID-19 infection is called a cytokine storm. The immune system, upon seeing the virus and its proteins, overreacts in its attempt to kill the invading virus. The infected person is left with brain fog, fatigue and other cognitive issues.

Banks and his team saw this reaction with the HIV virus and wanted to see if the same was happening with SARS CoV-2.

Banks said the S1 protein in SARS-CoV2 and the gp 120 protein in HIV-1 function similarly. They are glycoproteins—proteins that have a lot of sugars on them, hallmarks of proteins that bind to other receptors. Both these proteins function as the arms and hand for their viruses by grabbing onto other receptors. Both cross the blood-brain barrier and S1, like gp120, is likely toxic to brain tissues.

"It was like déjà vu," said Banks, who has done extensive work on HIV-1, gp120, and the blood-brain barrier.

The Banks' lab studies the blood-brain barrier in Alzheimer's, obesity, diabetes, and HIV. But they put their work on hold and all 15 people in the lab started their experiments on the S1 protein in April. They enlisted long-time collaborator Jacob Raber, a professor in the departments of Behavioral Neuroscience, Neurology, and Radiation Medicine, and his teams at Oregon Health & Science University.

The study could explain many of the complications from COVID-19.

"We know that when you have the COVID infection you have trouble breathing and that's because there's infection in your lung, but an additional explanation is that the virus enters the respiratory centers of the brain and causes problems there as well," said Banks.

Raber said in their experiments transport of S1 was faster in the olfactory bulb and kidney of males than females. This observation might relate to the increased susceptibility of men to more severe COVID-19 outcomes.

As for people taking the virus lightly, Banks has a message:

"You do not want to mess with this virus," he said. "Many of the effects that the COVID virus has could be accentuated or perpetuated or even caused by virus getting in the brain and those effects could last for a very long time."


Explore further  COVID-19 vaccines focus on the spike protein – but here's another target

More information: Elizabeth M. Rhea et al, The S1 protein of SARS-CoV-2 crosses the blood–brain barrier in mice, Nature Neuroscience (2020). DOI: 10.1038/s41593-020-00771-8
Journal information: Nature Neuroscience 

Provided by University of Washington 


Is Istanbul headed for another big earthquake?


MURAT SOFUOGLU
31 JAN 2020

In September last year, Istanbul was shaken by a magnitude 5.8 earthquake, triggering widespread panic. This is what experts think the future might hold for the city.

Istanbul is one of the world’s most picturesque cities located along the banks of the Bosphorous - a globally strategic waterway that divides Europe and Asia. What lies beneath the city though, doesn’t paint as beautiful a picture.

The city lies directly atop the dangerous North Anatolian fault line, marking the border between the Eurasian and Anatolian plates, the scene of some of the world’s most destructive earthquakes in history, claiming the lives of tens of thousands.

In the last five centuries, Istanbul has seen at least seven big earthquakes in 1509, 1719, 1754, 1766, 1894 and 1912. In 1999, the Izmit earthquake, the most recent big one killed several hundred residents of Istanbul along with 16,000 people living in the Marmara and northwest Black Sea regions.

Istanbul is sandwiched between the Black Sea in the north and the Sea of Marmara to the south.

On January 24 this year, another deadly earthquake with a magnitude of 6.8 hit Turkey’s eastern province of Elazig and its neighbouring cities, killing at least 41 people and wounding more than 1,600.

On September 26, it was once again jolted by a magnitude 5.8 earthquake, which panicked Istanbulites, triggering a long debate about the possibilities of another ‘big one’ in the city.

Which faults could affect Istanbul?

Sener Usumezsoy, who looks more like a bodybuilder or a cowboy than a geology professor, speaks with authority about the ancient fault lines of Istanbul, which lay underneath the waters of the Marmara Sea, located between the Bosphorus and the Dardanelles straits.

He is one of Turkey’s most prominent earthquake experts and remains measured about what might lie ahead for Istanbul
.
Sener Usumezsoy, a popular Turkish geology professor, speaks to TRT World about Istanbul’s earthquake risks in the city's Kadikoy district. In the picture behind him, the Sea of Marmara, under which some dangerous fault lines lay down. (Murat Sofuoglu / TRTWorld)

First and foremost, Usumezsoy thinks that while there are some risks for Istanbul, people should not fear a ‘big one’ because the fault lines beneath the Marmara Sea do not seem to contain the structure that could lead to a powerful earthquake.

Behind the presumed inevitability of a devastating earthquake lies one major misunderstanding. There is a misconception that the inactive north boundary fault line between Tuzla and Silivri, very close to Istanbul’s city centre, is part of the active North Anatolian fault, which has led to devastating earthquakes in the past across Turkey from east to west, according to Usumezsoy.
(Samet Catak/Enes Danis / TRTWorld)

In addition to this misunderstanding, the two big earthquakes in the Marmara Sea — which were triggered by the North Anatolian fault line in the late 19th Century and early 20th Century — have decreased the probability of a big earthquake in Istanbul, Usumezsoy says.

"In 1912, the western edge of the restless North Anatolian fault was broken in mainly two areas — one is close to the Tekirdag Basin, and another one is close to the Silivri Basin in the Marmara Sea," Usumezsoy explains.

As a result, currently, the fault line does not have enough seismic energy to lead to a big earthquake, the professor claims.

The 1912 earthquake in Tekirdag province was extremely destructive, with an estimated magnitude of 7.4 and killed around 3,000 people destroying nearly 25,000 houses in its wake.

Since 1912, seismologists have been debating whether the broken fault has accumulated considerable stress, and could lead to another big earthquake.

"Strong earthquakes occur when the fault zone becomes locked. Then tectonic strain accumulates, and the seismic energy is released in an earthquake," said Dietrich Lange, a leading academic for the GEOMAR Helmholtz Centre for Ocean Research Kiel (Germany), who conducted a comprehensive study in the summer on the fault lines in the Marmara Sea.

Lange believes that the North Anatolian fault has built up enough tectonic strain to trigger a big earthquake.

But Usumezsoy disagrees, saying that the latest Japanese research proves otherwise.


The map shows bathymetric features and the layout of five seafloor extensometers in an area close to the Silivri Basin in the Sea of Marmara. These measurements show that there are movements or creepings between stations designated by arrows and numbers, which indicate that the Silivri fault is not locked and as a result do not accumulate essential stress to trigger a big earthquake. (Samet Catak/Enes Danis / TRTWorld)

“If this fault has become locked, accumulating two centimetres tectonic strain per year, that means it should have accumulated at least two metres strain until today,” Usumezsoy says.

“However, research conducted by Japanese showed that in this part of the Marmara Sea, the fault has not been locked without accumulating two centimetres strain. Instead, much of the fault is creeping, which amounts to 1.5 centimetre per year,” he said.

Therefore, the probability of a big earthquake is significantly diminished, according to him. 


Strike-slip faults are vertical fractures where the blocks have mostly moved horizontally, building up strain and eventually leading to earthquakes. Turkey’s dangerous North Anatolian Fault (NAF) is a strike-slip fault. The map shows that NAF in the Sea of Marmara is not locked, instead it has about 1.5 centimetre slip rate per year, meaning that it is not producing enough strain to trigger a big earthquake. (Samet Catak/Enes Danis / TRTWorld)

Nearly 20 years before the 1912 earthquake, in 1894, the North Anatolian fault also broke on its south eastern edge, where it was moving from the Armutlu Peninsula westward to the Cinarcik Basin, in the Marmara Sea.

As a result, in this area, the North Anatolian fault does not appear to have enough seismic energy to lead to a powerful earthquake, affecting Istanbul, Usumezsoy asserts.

The 1894 earthquake killed hundreds of people and led to enormous destruction inside Istanbul’s old city, leaving its mark on the ancient metropolis’s landmarks from the monumental Galata Tower to the city's Byzantium-era walls.

(Samet Catak/Enes Danis / TRTWorld)

Since the last big one in 1999, the pressure on the North Anatolian fault in the Marmara Sea has concentrated on its southern branch. It is moving south, close to the southern shores of the Marmara Sea, according to Usumezsoy.

That means the North Anatolian fault’s southern branch, which is more active and under pressure, is moving further away from Istanbul.

Quake debate

Despite Usumezsoy’s assurances, after the recent earthquake in Silivri Basin, the big Istanbul earthquake debate resurfaced as both ordinary folks and experts passionately argue about its potential timing and magnitude.

The 4.6 and 5.8 earthquakes happened in the Silivri Basin, where a separate fault line in the middle of the Marmara Sea, which lies northward, was broken twice in late September. (Map 1)

No casualties were reported, but several buildings collapsed in Istanbul, and many were left marked by cracks
.
A man takes pictures of a damaged mosque after an earthquake in Istanbul, Turkey, September 26, 2019. (Murad Sezer / TRTWorld)

After the earthquakes in the Tekirdag Basin, the Cinarcik Basin and most recently in the Silivri Basin, all earthquake-watchers have turned their attention towards a tiny fault line in the Kumburgaz Basin, which moves from the middle of the Marmara Sea to Cekmece.

Where could another earthquake happen?

“This (Kumburgaz) fault, which has been said to have a length of 40 to 50 km, is now being expected to be broken. This is the one, which carries a risk to be broken at the moment. But because this fault is not part of the North Anatolian fault system, it can not create big earthquakes,” Usumezsoy told TRT World.

“Because the depth of the Kumburgaz fault is about 10 kilometres, it can not create an earthquake more than the magnitude of 6.5,” he said. 
(Samet Catak/Enes Danis / TRTWorld)

The depth of the Kumburgaz fault also proves that it’s not part of the North Anatolian fault system, which traverses the lithosphere at a depth of 20 kilometres across Turkey.

The magnitude of an earthquake is calculated by measuring its length and depth. As a result, the larger the area of the fault, the larger the earthquake. The same principle applies to the depth of the fault line.

“Magnitude represents the total energy released in the earthquake, which in turn depends on the area (length times depth) of the fault where slip occurs,” says Earthquake Country Alliance, an earthquake monitoring group, which aims to increase awareness and preparedness about earthquakes and tsunamis.

But other experts like Ronald Armijo, a French scientist, come to a different conclusion based on the assumption that the Kumburgaz fault lies further than Cekmece to Yesilkoy, defending a counter-argument that the high-risk fault has a length of 70 km, which means Istanbul could face a magnitude 7.2 earthquake.

Some other experts also claim that the allegedly active fault between Silivri and Tuzla will be broken once, leading to an earthquake of a magnitude of 7.6.

Usumezsoy disagrees with them, saying they are confusing a normal and possibly dead faultline between Tuzla and Cekmece with the North Anatolian fault, which is essential to Istanbul.

“Their mistake is a vital mistake to understand the dynamics of (Istanbul’s future earthquake),” the professor concludes. 

Source: TRT World

New constraints on alternative gravity theories that could inform dark matter research

by Ingrid Fadelli , Phys.org
Image produced during a simulation of the evolution of dark matter in the universe. Credit: Milennium-II Simulation.

While particle theories are currently the most favored explanations for dark mater, physicists have still been unable to detect dark matter particles in ways that would confirm or contradict these theories. Some theorists have thus been exploring new theories of gravity that clearly account for and explain the existence of this elusive type of matter. In order to obviate the need for dark matter, however, these theories should be aligned with cosmological observations gathered so far.


Two researchers at the Jet Propulsion Laboratory (JPL) and Princeton University have recently carried out a study aimed at better understanding what points alternative theories of gravity should address in order to effectively back the existence of dark matter in the universe. Their paper, published in Physical Review Letters, outlines a series of constraints that could help to determine the potential validity of alternative gravity theories.

The standard cosmological paradigm, ΛCDM , explains how the current universe developed from cosmic microwave background (CMB), essentially painting a 'picture' of the universe's development from its early days up until today. The evolution of the CMB's structure into galaxies and the present cosmic web structure could be justified by the existence of cold dark matter (CDM).

"We wanted to see if we could use the CMB data and the galaxy data available today to place some constraints on how an alternative gravity theory would need to behave if it was to explain dark matter," Kris Pardo, one of the researchers who carried out the study, told Phys.org. "Basically, if it is actually some alternative gravity that is responsible for dark matter, then it should be able to explain exactly how normal matter evolves from the CMB to today."

The core idea behind the study carried out by Pardo and his colleague David N. Spergel has already been explored by other researchers, including by Scott Dodelson at the Kavli Institute for Cosmological Physics in a paper published in 2011. Nonetheless, Pardo and Spergel were the first to actually calculate the function summarizing this idea.

"We showed that any theory that tries to explain dark matter by changing gravity (rather than by having a new particle) would need to have a very unique form," Pardo explained. "In fact, this form would be so unique that it would probably lead to some pretty crazy motions of galaxies near us, which we see no evidence for. So the simplest explanation for dark matter is still that it is some particle."

The recent study by Pardo and Spergel set new constraints on the specific qualities that alternative gravity theories should have in order to support the existence of dark matter. Interestingly, the researchers found that none of the theories of gravity proposed so far satisfy these constraints, which suggests that if dark matter can be explained by such theories, a valid theory has not yet been developed. In the future, their work could inform the development of alternative gravity theories that are more aligned with cosmological observations.

"In our study, we assumed that the alternative gravity theory had to be 'linear,'" Pardo said. "We're now looking at how to expand this to nonlinear theories."


Explore further   Study sets the first germanium-based constraints on dark matter

More information: What is the price of abandoning dark matter? Cosmological constraints on alternative gravity theories. Physical Review Letters(2020). 

Journal information:
Physical Review Letters

© 2020 Science X Networ
Restoring wetlands near farms would dramatically reduce water pollution

by Brian Flood, University of Illinois Chicago
Researchers at UIC and the University of Waterloo examined detailed data on wetland locations and nitrogen loads from fertilizer on farm fields throughout the U.S.
Credit: Dave Hoefler via Unsplash

Runoff from fertilizer and manure application in agricultural regions has led to high levels of nitrate in groundwater, rivers, and coastal areas. These high nitrate levels can threaten drinking water safety and also lead to problems with algal blooms and degradation of aquatic ecosystems.

Previous research has shown that wetlands improve water quality, but how much of an impact are wetlands having on nitrate removal now, and what improvements could wetland restoration deliver in the future?

Researchers from the University of Illinois Chicago and the University of Waterloo sought to evaluate these details at the U.S. scale and publish their findings in a new paper featured in the journal Nature.

Their study examines the positive effects of wetlands on water quality and the potential for using wetland restoration as a key strategy for improving water quality, particularly in the Mississippi River Basin and Gulf of Mexico regions.

The wetland essentially has a purifying effect when nitrate-laden water enters its boundaries. Chemical reactions take place that removes the harmful nitrate from the water, allowing for harmless nitrogen gas to be released into the atmosphere and cleaner water to flow downstream.

"Unfortunately, most wetlands that originally existed in the U.S. have been drained or destroyed to make way for agriculture or urban development. Ironically, areas with the biggest nitrate problems, due to agriculture and intensive use of nitrogen fertilizers, are also usually areas with the fewest numbers of remaining wetlands," said Kimberly Van Meter, UIC assistant professor of earth and environmental sciences and co-lead author of the paper.

The researchers used maps of remaining wetlands across the U.S. to quantify the amount of nitrate that is currently being removed by wetlands. Despite the high levels of wetland loss, their results suggest that nitrate loads in the Mississippi River might be approximately 50% higher than they are currently without the presence of wetlands.

The wetlands' significant contribution to current nitrate removal is important for two key reasons, according to UIC's Van Meter and her colleagues Frederick Cheng, Danyka Byrnes and Nandita Basu, all from the University of Waterloo.

"First, the Mississippi River is the largest source of nitrogen to the Gulf of Mexico and a major cause of the large dead zone that appears in the Gulf every summer. Second, protections for current wetlands have been eroded in recent years, especially with revisions of the Clean Water Rule under the Trump administration, which eliminated protections for approximately half of all U.S. wetlands," Van Meter said.

The researchers also carried out computer model simulations to better understand how wetland restoration might benefit water quality.

"We found that by targeting wetland restoration to areas in the U.S. with the highest levels of nitrate pollution, even a 10% increase in current wetland area could cut nitrate levels in rivers and streams by half," Van Meter said.

The cost of a wetlands initiative is estimated at $3.3 billion a year, an amount researchers described as feasible given current government spending levels. While that is twice the estimated cost of a non-targeted approach, the model showed it would remove 40 times more nitrogen.

"You get much more bang for your buck if wetland preservation and restoration are targeted," said Nandita Basu, professor of civil and environmental engineering, and earth and environmental sciences at the University of Waterloo and corresponding author of the paper. "From a policy perspective, it is dramatically more effective and efficient."

The authors also point out that various negative socio-economic outcomes stem from nitrate pollution in lakes and coastal areas. When algal blooms, which are generally considered to be unsightly and often release an unpleasant sulfur-like smell, take over a water body it usually limits recreational access for swimming, boating, and fishing and, thus, negatively affects tourism. Toxins associated with algal blooms also restrict fishing, resulting in financial problems for coastal fisheries. When cities rely on impacted water bodies for drinking water, the costs of water treatment also rise.


Explore further

More information: F. Y. Cheng et al. Maximizing US nitrate removal through wetland protection and restoration, Nature (2020). DOI: 10.1038/s41586-020-03042-5

Journal information: Nature

Provided by University of Illinois Chicago
River sediment history suggests it was climate change, not Mongol invasion that doomed Transoxania

by Bob Yirka , Phys.org
Trenching of an ancient irrigation canal north of the fortified settlement of Kuik Mardan (in the background) in Otrar Oasis. Credit: Willem Toonen.

An international team of researchers has found evidence in ancient river sediments that suggest climate change, not a Mongol invasion, ultimately doomed the ancient Transoxania civilization. In their paper published in Proceedings of the National Academy of Sciences, the group describes how they analyzed sediment samples from rivers and abandoned canals in the area and what they learned by doing so.

Transoxiana is the ancient name of a civilization that once lived in what is now part of Kyrgyzstan, Uzbekistan and Tajikistan—it was situated around the Otrar oasis in Central Asia. Prior research has suggested that the civilization was never able to recover from Mongol invasions in the early part of the 13th century. In this new effort, the researchers suggest the fall of the Transoxania civilization was much more complicated than that, and that there were likely a variety of factors involved.


Suspecting that climate change may have played a role, the researchers collected sediment samples from dry canals that had been used by the people of Transoxania. The canals had been built to corral floodwater from the Amu Darya and the Syr Darya rivers and to use it for irrigation. The researchers tested the samples using optically stimulated luminescence and radiometric dating to determine the time period during which the canals had been abandoned. They then conducted the same kinds of tests on river sediments in the area which gave them a history of river flow.

The researchers were able to see changing river flows exerted a negative impact on irrigation efforts, which would have made it difficult for the Transoxania people to feed themselves. Sadly, the drought came before and during the time when the Mongols arrived, making it almost impossible for the people in the area to defend themselves and survive—at least in the near term. The researchers found that after the Mongols had moved on, the rains returned for a period of time. The researchers believe that the people who lived there before the invasion recovered to some extent. But another drought ultimately led to migration to more hospitable locations.

The lush green corridor of the current Arys river in Kazakhstan; the high left bank was used for medieval floodwater farming . Credit: Willem Toonen.

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More information: A hydromorphic reevaluation of the forgotten river civilizations of Central Asia, Proceedings of the National Academy of Sciences (2020). www.pnas.org/cgi/doi/10.1073/pnas.2009553117

Journal information: Proceedings of the National Academy of Sciences

© 2020 Science X Network

Mountain hares in Scotland are failing to adapt to climate change, making them more vulnerable to predators

by Bob Yirka , Phys.org
Credit: Pixabay/CC0 Public Domain

A team of researchers from the U.S. and the U.K. has found that mountain hares in Scotland have not been changing their molt times in response to climate change. In their paper published in Proceedings of the Royal Society B, the group describes their study of mountain hares in Scotland.


Mountain hares in Scotland typically molt in late October each year. Their brown, warm-weather fur is replaced with snowy white fur that allows them to blend in with a snowy background, making it more difficult for predators to spot them. The reverse happens in late March.

Prior research has shown that many species have been adapting to a warming planet by molting later in the fall and earlier in the spring. In this new effort, the researchers wondered if the snow hares in Scotland were doing likewise. To find out, they conducted multiple field studies around Scotland, recording molt times at different elevations and times of the year. They then obtained weather data describing changes in snow patterns going back a half-century for the same area.

The researchers found that while snow patterns have changed dramatically, molt times for mountain hares have not changed in either the fall or the spring. And because molt times did not change, the number of days that the hares were mismatched with their environment increased by 35 each year. And such mismatches, they note, could place the hares at risk.

In trying to understand why the hares were not changing their molt times, which would be an evolutionary process, the researchers came up with three theories. The first was that the population of mountain hares is too small to allow for changes in the short term. The second was that they are simply a species that takes longer to react to climate changes. And the third possibility was that the hares were not more at risk from predators despite being more exposed because there are too few predators left in the area—humans have reduced their numbers to encourage growth in grouse populations for hunters.


Explore further  Evolutionary clock ticks for snowshoe hares facing climate change

More information: Marketa Zimova et al. Lack of phenological shift leads to increased camouflage mismatch in mountain hares, Proceedings of the Royal Society B: Biological Sciences (2020). DOI: 10.1098/rspb.2020.1786

Journal information: Proceedings of the Royal Society B

© 2020 Science X Network
Beirut explosion: Judge suspends blast probe amid political pressure
Two ministers charged in explosion investigation have requested that Judge Fadi Sawwan be removed from proceedings


Helicopter battles fire at scene of explosion at port of Lebanon's capital Beirut on 4 August (AFP/File photo)

By MEE and agencies
Published date: 17 December 2020 

The judge overseeing an investigation into the massive explosion that rocked Beirut in August has suspended the probe after two ministers he charged with negligence requested that he be removed, according to judicial sources.

Beirut explosion: Lebanon's investigation on edge following political backlash
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Judge Fadi Sawwan on 10 December issued charges against former caretaker prime minister Hassan Diab and high-ranking former ministers Ali Hassan Khalil, Ghazi Zaiter and Youssef Fenianos over the 4 August blast.

The four were charged with "negligence and causing death to hundreds and injuries to thousands more" in one of the largest non-nuclear explosions in history.

Lebanon's top Cassation Court is now expected to rule on their request for Sawwan to be removed from his post, AFP reported.

"Until then, all investigation proceedings are suspended," a senior court judicial official told the news agency on condition of anonymity.

'This is a security coup'


Earlier this week, a source close to Judge Sawwan told Middle East Eye that the investigation into the blast has been the target of a scathing "political campaign".

Lebanon's politicians have rallied around the argument that any indictment of a minister should be submitted to a vote in parliament.

The four indicted ministers were the first politicians to be charged since the beginning of the investigation, which opened on 14 August. Other officials, including the country’s justice minister and some predecessors, were interrogated, but as witnesses rather than as defendants. 


Beirut explosion: Judge charges PM, ex-ministers over August port blast
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Diab, who resigned in the wake of the explosion, already testified before Sawwan in September.

Karim Nammour, a lawyer and board member at rights group Legal Agenda, warned last week that the independence of the legal probe was at risk.

"The judiciary is being directly targeted," he told MEE at the time, adding that Lebanon has become far more militarised in recent months. "When you are discrediting the role of the judiciary … this is a security coup in every sense of the word."

Nammour noted that the judiciary has been "discredited publicly", especially as judges have begun to defy political orders. Last month, Mohammed Fahmi, the caretaker interior minister, claimed that "95 percent of judges are corrupt".

The explosion that rocked the capital this summer, killing about 200 people and wounding thousands, was caused by almost 3,000 tonnes of explosive ammonium nitrate left unattended at the port for more than half a decade.

The fact that little light has been shed on the circumstances that led to Lebanon's worst peacetime disaster four months after the blast has caused outrage.

It is also fuelling mistrust among international donors whose support is needed if Lebanon is to stand a chance of surviving its worst-ever economic crisis.