Март 2020 г.

Российская наука и мир (по материалам зарубежной электронной прессы)

CONTENTS / ОГЛАВЛЕНИЕ


• "Impossible" superconducting compound synthesized by scientists
• Novel manganese-zinc ferrite nanoparticles can potentially be used in cancer treatment
• New superhydrophobic material can purify water effectively from oil products
• Lifting Russia’s accident reactors from the Arctic seafloor will cost nearly €300 million
• Icarus is launched
• Huawei, MIPT establish lab to develop AI tech
• European Mars rover delayed until 2022
• Astrophysicists wear 3D glasses to watch quasars and study active galactic nuclei
• A mysterious 25,000-year-old structure built of the bones of 60 mammoths
• Russia aims to revive science after era of stagnation
• The price of Russia-China research collaborations
• Russian scientists break Google’s quantum algorithm
• Researchers reveal secret of 18th-century portrait from Russia’s Tretyakov Gallery
• Russian researchers explain why new pathogenic viruses are so hard to detect
• Studying the mechanism for avian magnetic orientation

Российские (Сколковский институт науки и технологий) и китайские (Цзилиньский университет) физики синтезировали несколько новых сверхпроводников из водорода и редкоземельного металла празеодима. Одно из соединений до сих пор считалось невозможным с точки зрения классической химии.

Scientists have created new superconducting compounds of hydrogen and praseodymium, a rare-earth metal, one substance being quite a surprise from the perspective of classical chemistry. The study helped find the optimal metals for room-temperature superconductors. The results were published in Science Advances.
A theory that has evolved in the past fifteen years assumes that hydrogen compounds (hydrides) can make excellent superconductors; that is, substances that have zero electrical resistance when cooled down to a certain temperature and are capable of carrying electricity without any losses, which is particularly valuable for power networks. However, the sticking point that scientists are still striving to work out is the temperature at which a substance achieves superconductivity. For most compounds it is very low, so superconductors used in real life are typically cooled with liquid helium using complex and costly equipment. Physicists are busy searching for a substance that achieves superconductivity at room temperature. One of the likely candidates is metallic hydrogen, but the pressure required to produce it exceeds 4 million atmospheres!
A group of Russian scientists from Skoltech and Chinese researchers from Jilin University published a paper, with Dmitry Semenok and Di Zhou as the first authors, featuring their research results. Their team created compounds of hydrogen and praseodymium, a metal from the lanthanide series, and studied their physical properties. The authors synthesized several compounds with different ratios of atoms for each element. To do this, they placed praseodymium and hydrogen samples in a special chamber where they were pressed between two cone-shaped diamonds so that pressure increased to 40 GPa, and were laser-heated. The elements got compressed and reacted to form the compound PrH₃. The downside is that diamonds tend to become too fragile and break up when coming into contact with hydrogen.
The scientists then replaced pure hydrogen with ammonium borane, a compound containing a large amount of hydrogen readily released when heated and reacting with praseodymium. The researchers found this method to be more effective and continued to use it in further experiments. By increasing the pressure, they obtained PrH₉. Earlier, they had synthesized compounds of hydrogen and lanthanum, another metal from the same series, using the same technique. The molecules they obtained are special in that they are an "outlaw" in classical chemistry, as they do not obey by its rules. Even though, formally, the praseodymium atom’s electronic structure is such that it does not allow it to bond with so many other atoms, the existence of such "improper" compounds can be predicted by complex quantum calculations and proved by experiments.
Also, the scientists investigated the superconductivity of the new substances by measuring electrical resistance at different temperatures and pressures and found that praseodymium hydride becomes superconducting at -264 °C, which is much lower compared to LaH₁₀, although the two compounds are similar both chemically and structurally. The authors looked into the reasons for the difference in the characteristics by comparing their results to other studies and found that the metal’s position in the periodic table and its properties play a pivotal role. It transpired that praseodymium atoms act as donors for electrons: unlike their neighbors, lanthanum, and cerium, they carry small magnetic moments that suppress superconductivity which can still occur, although at lower temperatures.
"We applied the method used previously to synthesize lanthanum hydrides and succeeded in creating new superconducting metallic praseodymium hydrides. We made two main conclusions. First, you can get abnormal compounds with compositions having nothing to do with valence; that is, the number of bonds an atom can have with other atoms. Second, we validated the new principle for creating superconductors. We found that the metals from the "lability zone" located between groups II and III of the periodic table are the best candidates. The elements nearest to the "lability zone" are lanthanum and cerium. Going forward, we will proceed from this finding to obtain new high-temperature superconductors," said Skoltech and MIPT professor, Artem Oganov.

Российские ученые из Университета ИТМО, МГУ и группы компаний AMT&C синтезировали наночастицы, содержащие цинк, марганец и железо и способные менять свои магнитные свойства в зависимости от температуры. Благодаря этому их можно будет использовать в лечении онкологии методом гипертермии - локального нагрева и уничтожения раковых клеток, не повреждая при этом здоровые ткани, поскольку магнитные свойства частиц позволят очень точно контролировать температуру.

A group of Russian scientists has synthesized manganese-zinc ferrite nanoparticles that can potentially be used in cancer treatment. Due to their unique magnetic properties, the particles can serve as deactivators of affected cells while having almost no negative impact on healthy tissues. The results have been published in the Journal of Sol-Gel Science and Technology.
One of the most important global goals in today's medicine is finding ways to combat cancer. Currently, there are several kinds of treatments with differing effectiveness and various side effects. In most cases, the treatment causes harmful impact not only to cancer cells but also the adjacent healthy tissues or the body at large.
Magnetic fluid hyperthermia is a promising method that can help alleviate the side effects of cancer treatment. This method involves introducing a magnetic nanoparticles-containing sol into a tumor followed by its exposure to a variable magnetic field. This causes the heating of the nanoparticles and leads to the deactivation of cancer cells. However, the majority of the materials used for this purpose are toxic to the body. What is more, the particles continue to heat up to relatively high temperatures, which entails serious damage to healthy tissues.
These problems could be solved by the application of special nanoparticles which can change their magnetic properties depending on the temperature. In physics, there is such a notion as the Curie temperature (also known as the Curie point), which is the temperature at which a sharp decrease in magnetization is observed.
"When the Curie temperature is reached, a ferromagnetic changes into a paramagnetic, consequently the particles cease to be as susceptible to the magnetic field and their further heating stops. When the temperature drops back again, the particles resume their heating. Essentially, we observe a self-management of temperature in a narrow range. If we select a composition that experiences such a transition at the temperature we need, then it could prove effective for magnetic fluid hyperthermia." (Vasilii Balanov, a Master's student at ITMO University and one of the research's authors).
Choosing the material, the scientists opted for ferrites - compounds of iron oxide (III)Fe2O3 with oxides of other metals. Generally, thanks to their properties, these materials are widely applied in computer technologies, but, as it turned out, they can also be used for medical purposes.
"We took the particles with the general formula Zn(x)Mn(1-x)Fe2O4, in which zinc and manganese are selected in a certain proportion," expounds Vasilii Balanov. "They don't have a toxic effect on the body, and with the right ratio of manganese and zinc we were able to achieve a Curie temperature in the range of 40-60 degrees Celsius. This temperature allows us to deactivate cancer cells, concurrently, the short-term thermal contact is relatively harmless to healthy tissues."
As of now, the scientists have already synthesized the nanoparticles and studied their magnetic properties. The experiments confirmed that the material doesn't heat up above 60 degrees Celsius when exposed to a variable magnetic field. Coming next will be the experiments on living cells and, if these are successful, on animals.

Томский политехнический университет и Университет Лилля (Франция) разработали эффективный сорбент для очистки воды от нефтепродуктов, взяв за основу обычную бытовую полиуретановую губку и добавив в ее структуру соли диазония. В результате губка приобрела свойство отталкивать воду и поглощать молекулы нефтепродуктов.

A novel material with the ability to effectively purify water from oil products has been developed by researchers at Tomsk Polytechnic University in collaboration with the University of Lille (France). This material is based on a usual household polyurethane sponge.
The researchers made it superhydrophobic, that is, it repels water, while absorbing oil product molecules effectively. The study outcomes were reported in the Separation and Purification Technology journal.
"New oil production methods, especially the ones related to production on the seabed and ocean floor, raise up the risk of spills. We all know about the environmental impact of the accident that happened on a drilling platform in the Gulf of Mexico in 2010. Therefore, one of the most urgent scientific problems is to obtain selective sorbents capable to extract oil products from a water-oil mixture, avoiding interactions with water", said Pavel Postnikov, Associate Professor, TPU Research School of Chemistry and Applied Biomedical Sciences, Tomsk Polytechnic University. Postnikov added, "The latter point is crucially important since interactions with water basically result in some resultant products to end up in the water and affect the ecosystem. Furthermore, water saturation drops the sorbent effectiveness. Therefore, we had to find affordable material and make it hydrophobic and efficient for the mentioned goal. We decided in favor of a regular washing sponge."
The sponge was made hydrophobic by using special organic compounds called diazonium salts. The sponge was immersed in an aqueous solution with diazonium salts and heated to a temperature of 60 °C.
The resulting active radicals acted on the sponge and formed new organic groups with hydrophobic properties on the surface. These organic groups are sensitive to oil products at the same time. They serve as sorbents that selectively absorb oil molecules.
"The second issue is to find an efficient way to remove this material from water. We chose a magnetic sorbent collection. We added iron nanoparticles in the structure of the sponge, obtained by our original method and characterized by increased susceptibility to nonpolar molecules. We also added hydrophobic organic groups. As a result, we obtained material that almost does not interact with water despite the fact that it is a sponge" (Pavel Postnikov).
In water, petroleum products exist in an emulsion form. This indicates that their microscopic droplets are distributed in a different liquid, which, in this case, is water. The researchers say in reality, such emulsions are highly stabilized in general, making it hard to isolate them into separate components.
We tested our material with both highly stabilized and low stabilized emulsions. The experiments demonstrated that the material is excellent. We also tested its effectiveness on industrial oils that can pollute natural water bodies. The material also showed its high efficiency. (Pavel Postnikov).
Moreover, the studies revealed that it is possible to reuse the novel material repeatedly for several times.
Pavel stated, "In experiments, we used it at least five times and there was no drop in its efficiency."

Российские и европейские эксперты сходятся во мнении, что захороненные в Карском море ядерные реакторы советских подводных лодок и атомных ледоколов следует поднять и утилизировать как можно скорее. Наиболее срочные меры необходимо принять в отношении пяти подлодок и одного ледокола, однако суммарная стоимость работ, по подсчетам экспертов, составляет почти 300 млн евро, которые в российском бюджете не предусмотрены.

Russian and European experts agree that the dumped Soviet-era nuclear reactors in the Kara Sea can’t stay on the seafloor forever.
The Soviet Union used the waters east of Novaya Zemlya to dump accidental reactors, spent nuclear fuel and solid radioactive waste from both the navy and the fleet of nuclear-powered civilian icebreakers. About 17,000 objects were dumped in the period from the late 1960s to the late 1980s. Most of the objects are metal containers with low- and medium level radioactive waste. The challenge today, though, are the reactors with high-level waste and spent uranium fuel, objects that will pose a serious threat to the marine environment for tens of thousands of years if nothing is done to secure them.
According to the Institute for Safe Development of Nuclear Energy, part of Russia’s Academy of Science, the most urgent measures should be taken to secure six objects that contain more than 90% of all the radioactivity. It is the information site for Russia’s submarine decommissioning program that informs about the plans.
The reactors from the submarines K-11, K-19 and K-140, plus the entire submarine K-27 and spent uranium fuel from one of the old reactors of the Lenin-icebreaker have to be lifted and secured. Also, the submarine K-159 that sank north of Murmansk while being towed for decommissioning in 2003 have to be lifted from the seafloor, the experts conclude. Special priority should be given to the two submarines K-27 in the Kara Sea and K-159 in the Barents Sea.
The study report made for Rosatom and the European Commission has evaluated the costs of lifting all six objects, bringing them safely to a yard for decommissioning and securing the reactors for long-term storage. The estimated price-tag for all six will €278 millions, of which the K-159 is the most expensive with a cost of €57,5 millions. Unlike the submarines and reactors that are dumped in relatively shallow waters in the Kara Sea, the K-159 is at about 200 meters depth, and thus will be more difficult to lift.
Lifting the K-27, transporting to a shipyard for decommissioning and long-term storage in Saida Bay will come at a price of €47,7 millions the report reads. The work can be done over an eight years period, according to the expert. But, as the expert-group underlines, the €278 millions funding does not exist in any Russian Federal budgets today.

10 марта начала работу немецко-российская орбитальная система слежения за животными «Икар», созданная в рамках совместного проекта Общества Макса Планка, Германского центра авиации и космонавтики (DLR) и Российского космического агентства. «Икар» поможет ученым изучать места обитания и пути миграции различных видов животных, а также собирать данные о распространении семян растений и патогенных микроорганизмов. Полученная информация будет храниться в онлайн-базе, доступной для ученых всего мира.

The German-Russian observation system for animal migration Icarus, went into operation today. With the cooperation project of the Max Planck Society, the Russian space agency Roskosmos and the German Aerospace Center (DLR), scientists hope to investigate the migratory routes of various animal species. After the system is switched on, there will be a test phase lasting several months. During this time, the transmitters as well as the system components on the ground and on board the ISS will be tested. After all tests are completed, Icarus is expected to be available to users in autumn 2020.
With Icarus, the scientists hope to observe the migratory movements of birds and follow the migration routes of mammals and insects. The information should primarily be used for behavioural research and animal welfare. It should also provide data on the possible spread of plant seeds and pathogens. Martin Wikelski from the Max Planck Institute of Animal Behavior in Radolfzell is the scientific Director of the experiment.
In order to obtain the desired data, the researchers plan to equip different animal species with miniature transmitters (tags). "The tags record the position and movements of the animal together with environmental data such as temperature and air pressure", explains Johannes Weppler, Icarus project manager at DLR Space Management. "The data will then be stored locally before being sent into space". An integrated computer program in the transmitter will compare the orbit of the ISS with its own positional data. As soon as the space station is within radio range, the transmitter and receiver module of the tag will be activated. It will then make contact with the Icarus antenna on the outside of the ISS.
The on-board computer will then process the data and forward them to the Russian ISS control centre in Moscow. From there, the data will be forwarded to the German and Russian scientists. After an initial evaluation, the information will be stored in an online data base, the Movebank. Scientists around the world will then be able to access this data and create their own analyses. They are coordinated by the Max Planck Institute of Animal Behavior in Germany and the Institute of Geography of the Russian Academy of Sciences.
Test operation
During test operations, the Icarus system will initially communicate only with a ground station of SpaceTech GmbH in Immenstaad am Bodensee. The station will simulate the signals from animal transmitters. Mobile tags will be gradually added - later also on animals. Engineers from Germany and the Russian partner RKK Energia will measure the background noise in the frequency range of Icarus. This will enable them to identify possible sources of interference.
A second aspect of the test operation will be to measure the signal strength and transmission time of the Icarus antenna when it sends commands to the tags to reprogram them. After two to three months, the test operation will be extended to the territory of the Russian Federation. The overall system will thus be fine-tuned to ensure maximum performance and reliability. The initial scientific data is expected towards the end of the four-month test phase.
Second chance
The commissioning of Icarus had originally been planned for summer 2019. However, a technical defect in the on-board computer of the Icarus system upset the plans. Thanks to the astronauts on board the ISS, the defective computer was removed. In September 2019, it returned to earth with an unmanned Soyuz flight.
The German and Russian experts then analysed the source of the error and simultaneously prepared a replacement computer for the launch to the ISS. Finally, in December 2019, the new computer took off from Baikonur on the Russian freighter Progress MS-13 and reached the ISS shortly afterwards. It was then installed by the astronauts and switched on for the first time shortly before Christmas. Because this went as planned, the commissioning will now be resumed.

Московский физико-технический институт и китайский технологический гигант Huawei создали совместную лабораторию для исследований и разработок в области искусственного интеллекта и глубокого обучения на базе Физтех-школы прикладной математики и информатики.

The Moscow Institute of Physics and Technology has established a joint laboratory with Huawei Russian Research Institute. The project is part of a strategic partnership between the Chinese tech giant and the Phystech School of Applied Mathematics and Informatics at MIPT. The lab will focus on research and development in the field of artificial intelligence and deep learning.
This format for cooperation is a way to tap into the energy and expertise of both the academic community and the industry leaders, in order to develop breakthrough technologies and create advanced and convenient devices. As of today, Huawei has joint labs at 10 Russian universities and research centers. The new project at MIPT is an important step in developing Russia’s ecosystem of science and education.The new lab’s priority lines of R&D are:
• Developing neural network algorithms for computer vision, machine learning, and artificial intelligence.
• Developing methods for computational photography and image enhancement using mathematical modeling and advanced algorithms.
• Solving mathematically complex problems toward the creation of algorithms for simultaneous search and positioning.
"The Phystech School of Applied Mathematics and Informatics is a nationwide leader in terms of graduate quality in the field of mathematics and information technology, and this stems in large part from the union of academia and the industry," the school’s Director Andrey Raigorodskiy said. "We are always open to cooperation and prepared to tackle the interesting and ambitious problems faced by our partners. More than five joint projects between Huawei and our Phystech School are up and running already, and this number is bound to grow. We intend to establish a joint academic department with the company and further the research in the field."
"For Huawei, opening joint labs is a way to make an investment into the future of the Russian ecosystem of science and education. MIPT is our long-standing partner in both research and academic programs. We are committed to this long-term cooperation and intend to help the Institute to train specialists in deep machine learning and computer vision," noted Ivan Mazurenko, the director of the Technology Center for Intelligent Systems and Data Science at the Huawei Moscow Research Center.
"This lab is a vehicle for sharing the most relevant and challenging problems faced by the global information technology industry. It enables Russian scientists to conduct fundamental research and develop cutting-edge technology, as well as become world-class specialists without the need to leave Russia," Mazurenko added. "Importantly, this integration offers an opportunity for students to align their graduation theses with the lab’s research. The collaboration also envisions joint events, including conferences, seminars, and open lectures."

Роскосмос и Европейское космическое агентство объявили о переносе запуска совместной миссии «ЭкзоМарс» на 2022 год - в следующее астрономическое окно, когда Земля и Марс окажутся друг от друга на минимальном расстоянии, что случается раз в два года. Это уже второй перенос - первоначально миссия по поиску следов жизни на Марсе была запланирована на 2018, потом на 2020 год. На сей раз возникли проблемы с парашютной системой, солнечными батареями и электропроводкой. Сказалась и вспышка коронавируса, осложнившая обеим сторонам рабочие поездки.

Multiple technical issues will delay the launch of the ExoMars mission for 2 years until 2022, the European Space Agency (ESA) and its Russian counterpart, Roscosmos, announced today. ExoMars includes a Russian-built landing station and an ESA rover that would drill 2 meters below Mars’s surface to look for signs of past or present life. Now, just 4 months from its originally planned launch, the mission has been postponed because of problems with its parachute system, solar panels, and electrical wiring.
"We cannot really cut corners," said ESA Director General Jan Wöerner today at a press conference, following a meeting with Roscosmos chief Dmitry Rogozin. "It was a very tough decision, but I’m sure it was the right one."
Although the issues could be resolved in the next few months, Wöerner said there was not enough time to test the mission’s software system on the final flight-ready spacecraft. He did not want a repeat of the failure of ESA’s first Mars lander, 2016’s Schiaparelli, which crashed because of a software error during its descent.
Once repairs and testing are complete - probably by the end of the year - the lander and rover will be put into storage until the next launch window in the autumn of 2022, when the planets are aligned to allow the quickest journey. Scientists who have spent decades building instruments for the mission are philosophical about the delay. "Such is life. It’s the way it goes," says Valérie Ciarletti of the University of Paris-Saclay. "Space missions are like this," says Francesca Esposito of the Astronomical Observatory of Capodimonte.
Problems with the parachutes emerged last year during high altitude drop tests. The parachute fabric was torn while being pulled from its bag. Following redesigns, NASA and ESA engineers carried out successful ground tests at NASA’s Jet Propulsion Laboratory. But crucial drop tests in Oregon had to be delayed because the testing company had to perform parachute tests for Boeing’s Starliner crewed spacecraft. The ExoMars chute tests are expected in the coming weeks.
Meanwhile, environmental testing in Cannes, France, revealed the failure of glue holding solar panels to the rover, named after British DNA pioneer Rosalind Franklin. ESA’s Director of Human and Robotic Exploration David Parker told the press conference that this was partly expected from earlier studies. Once the rover has completed its tests in Cannes and is returned to its manufacturer in Turin, Italy, the panels will be attached with "additional mechanical fastenings," Parker said.
The lander, which doubles as a base station with sensors to study Mars’s interior, atmosphere, and weather, had four components that malfunctioned electrically during testing, Wöerner said, and have been returned to their manufacturers for modification. All these issues have delayed an overall test of the spacecraft’s software system, which must be carried out on the complete spacecraft. Insiders say that right now, the mission has used up all its time contingency and is 2 weeks behind schedule. "We have to wait until it is fully repaired," said ExoMars project manager François Spoto. "That’s why we need a delay."
Wöerner said the mission in 2022 would go ahead with the same launcher and landing site. There are no plans to add new instruments to the spacecraft, but ESA has offered instrument teams the chance to tinker with their devices and swap out components if needed. However, a delayed launch will mean ExoMars will not join two other Mars rovers planned for launch during the July/August launch window. NASA’s Perseverance rover is on track, and China plans to send a small rover along with an orbiter.
That’s a shame, Ciarletti says, because ExoMars and Perseverance "would have benefitted from operating at the same time." Both rovers have ground-penetrating radar to study the top few meters of soil beneath the surface and the Rosalind Franklin rover’s deep sampling drill would have helped both missions to understand what the radar was seeing. And that, in turn, could have helped Perseverance in its goal to collect and store samples of rock and soil for that would later be brought back to Earth by a Mars sample return mission. Researchers still hope that Perseverance may last beyond its nominal 2-year mission and overlap with ExoMars. Wöerner said the delay would not impact on ESA’s plans to collaborate with NASA on the sample return missions next decade.
For all the disappointment in the delay, Ciarletti is still OK with it. Schiaparelli was a technology demonstrator, but the hopes of hundreds of scientists ride with ExoMars. "The scientific payload is impressive. It would be a nightmare if it just crashed on Mars," she says.

Российско-греческая группа астрофизиков нашла способ определять происхождение и природу света квазаров по его поляризации. Способ аналогичен 3D-очкам, в которых один глаз видит свет горизонтальной поляризации, другой - вертикальной, за счет чего получается объемный эффект.

A team of researchers from Russia and Greece has shown a way to determine the origins and nature of quasar light by its polarization. The new approach is analogous to the way cinema glasses produce a 3D image by feeding each eye with the light of a particular polarization: either horizontal or vertical. The authors of the recent study in the Monthly Notices of the Royal Astronomical Society managed to distinguish between the light coming from different parts of quasars - their disks and jets - by discerning its distinct polarizations.
Active galactic nuclei, also known as quasars, are massive black holes with matter orbiting around them. They emit two oppositely directed jets of plasma traveling out into space at close to the speed of light.
Any massive black hole has matter orbiting around it, slowly falling toward it and emitting light. This matter forms what is known as an accretion disk. Due to a mechanism that is not yet fully understood, part of the matter approaching the black hole makes an escape. It is accelerated to tremendous velocities and expelled along the black hole’s axis of rotation in the form of two symmetric jets of hot plasma. When a quasar is observed, the radiation picked up by a telescope comes from the jets, the accretion disk, and also from the stars, dust, and gas in the host galaxy.
To study galactic nuclei, researchers use a range of telescopes. Prior research had shown that the parts of a quasar emit two different kinds of light, technically referred to as distinctly polarized light.
Most of the telescopes operate in the optical range and see a galactic nucleus as a tiny faraway dot. They cannot tell which part of the quasar the light comes from and where the jet points if it happens to be the light source. All an optical telescope can do is measure the polarization of light, which has been shown to contain clues about the origins of that radiation.
Radio telescopes offer a much better resolution and produce an image that reveals the direction of the jet. However, these telescopes pick up no radiation from the most interesting central region, which includes the accretion disk.
The astrophysicists therefore had to combine the strengths of both types of telescopes for a detailed view of quasars.
Yuri Kovalev, who heads the MIPT Laboratory of Fundamental and Applied Research of Relativistic Objects of the Universe, commented: "The fact that jet radiation was polarized was known. We combined the data obtained by radio and optical telescopes, and showed that the polarization is directed along the jet. The conclusion from this is that hot plasma must be moving in a magnetic field that is coiled like a spring."
But there’s more to it.
"It turned out that by measuring the polarization of the light picked up by the telescope, we can tell which part of radiation came from the jet and determine its direction," another co-author of the study, MIPT’s Alexander Plavin said. "This is analogous to how 3D glasses enable each eye to see a different picture. There is no other way to obtain such information about the disk and jet with an optical telescope."
The findings are important for modeling black hole behavior, studying accretion disks, and understanding the mechanism that accelerates particles to nearly the speed of light in active galactic nuclei.

Британские, российские и американские ученые вычислили возраст костей мамонта, из которых было построено сооружение на стоянке Костенки-11, обнаруженной в Воронежской области несколько лет назад. Круглая постройка диаметром 12 метров и возрастом около 25 тысяч лет использовалась, по некоторым признакам, для хранения продуктов, а также, возможно, в ритуальных целях.

A jaw-dropping example of Ice Age architecture has been unearthed on Russia’s forest steppe: a huge, circular structure built with the bones of at least 60 woolly mammoths. But exactly why hunter-gatherers enduring the frigid realities of life 25,000 years ago would construct the 40-foot diameter building is a fascinating question.
"Clearly a lot of time and effort went into building this structure so it was obviously important to the people that made it for some reason," says Alexander Pryor, an archaeologist at the University of Exeter (U.K.). He is the lead author of a new study published this week in the journal Antiquity describing the find at Kostenki, a place where many important Paleolithic sites lie clustered around the Don River.
The ancient builders did leave some clues. Fires once burned within the structure and food scraps, including vegetables, remain. Several pits containing mammoth bones lie just outside of the bone circle and may suggest food storage. "You obviously get a lot of meat from a mammoth," Pryor said, "so the idea that there were food processing and food storage activities going on at the site is something that we want to investigate more."
To some, though, the grandeur of the structure suggests more than practical significance. "People have also speculated a lot about a likely ritual element to this and it’s really hard to say what that might have been," Pryor adds. "Ritual is embedded in human lives in all sorts of ways. The fact they might have designed a structure of this type as part of both their ritual and their sustenance activities is very reasonable."
Mammoth-bone buildings are well-known to archaeologists. Similar structures have been found across Eastern Europe, albeit on a much smaller scale, a few meters in diameter. These sites, including others found at Kostenki during the 1950s and '60s, date back as far as 22,000 years. Researchers have generally considered them to be dwellings or "mammoth houses" that helped their builders cope with frigid temperatures near the nadir of the last Ice Age. The new structure (first discovered at Kostenki in 2014) is 3,000 years older.
"What a site!" says Penn State University anthropologist Pat Shipman, who wasn’t involved in the research. "I am completely intrigued as these remarkable finds differ meaningfully from previously discovered ones and can be more carefully and fully studied with modern techniques."
The site stands out most obviously for its scale. "The size of the structure makes it exceptional among its kind, and building it would have been time-consuming," says Marjolein Bosch, a zooarchaeologist at the University of Cambridge. "This implies that it was meant to last, perhaps as a landmark, a meeting place, a place of ceremonial importance, or a place to return to when the conditions grew so harsh that shelter was needed," Bosch was not involved with the new research on this " truly exceptional find" but has personally visited the site. Indeed, the structure’s sheer size makes it an unlikely everyday home. "I cannot possibly imagine how they would have roofed over this structure," Pryor said.
The smaller mammoth houses feature more definite cooking hearths, and they contain the remains of reindeer, horse and fox, which suggests the people in them were living on whatever they could find in the area. The new mammoth bone structure lacks evidence of other animal remains. "It’s almost exclusively woolly mammoth remains and that is one of the interesting things about it," Pryor said.
"With no other animal bones, this doesn’t look much like a dwelling where people lived for a while," Shipman added.
Intriguingly, the new structure is the first of its kind to yield evidence that its occupants burnt wood inside and not just bone. "It’s the first time anyone’s found large pieces of charcoal inside one of these structures. So it does show that trees were in the environment," Pryor said.
Tree ring widths in the charcoal are narrow, suggesting the trees probably struggled to survive in that landscape. Previous studies suggested that even on the Ice Age’s arid steppes, coniferous trees would have endured in forests stretching along riversides like those close to Kostenki - a draw for people looking to survive.
Still, if people weren’t living in the structure, then why did they make fires?
"Fire in the past can be seen as a tool much the same as chipped stone implements and worked bones are," Bosch says. Fires provided heat and light, barbecued and roasted food, dried meat for storage and processed glues for stone-tipped tools. "Here, the fires were lit inside a structure and its use as a light source seems intuitive," she says. "If the authors are correct in their assumption of its use as a place for food storage, it may also have been used to dry meat." There may be ways to test these ideas. Finding drops of fat on the floor, for example, could show that meat was dried over the flames.
The local diet also appears to have featured a smorgasbord of vegetables. By using water and sieve flotation techniques, the team discovered pieces of plant tissue among the charcoal. "This is the first time we have a plant food component discovered in any of these structures," Pryor says. His team hasn’t identified specific species yet but notes that the tissues are like those found in modern roots and tubers such as carrots, potatoes or parsnips.
The astounding assemblage of bones from more than 60 mammoths raises the question: Where did they all come from? Scientists aren’t sure if the animals were hunted, scavenged from sites of mass deaths or some combination of the two.
"There must be something about the topography of the site that makes it a place where, over and over, herds of mammoths are coming through and can be killed or will be killed naturally, like at a river crossing," says Penn State’s Pat Shipman. "I can imagine no way [these] people could possibly kill 60 mammoths at a time, because proboscideans (the order of mammals to which both mammoths and living elephants belong) are smart and catch on if members of their herd are being killed, even with modern automatic weapons."
Further studies of the mammoth bones will yield more clues about their source. Some were arranged in the same order and position as they were in the skeleton. "This means that the bones were brought to the site as body part which some soft tissue (skin, muscle, and tendons) still attached," Bosch said. "Therefore, they must have been transported before carnivores had the chance to eat and clean the bones. This implies that the builders had early access to the mammoth remains."
Shipman adds: "I want to know if the bones have been processed or transported or if we are looking at whole skeletons or carcasses piled up for future use. Moving a dead mammoth cannot have been easy even if it was largely de-fleshed."
However the mammoths got here, their presence was crucial to the humans living in the area. Lioudmila Lakovleva of the French National Centre for Scientific Research notes that "the complete settlement shows several mammoth bone dwellings, walls, enclosure, pits, working areas, hearths, dumping areas and butchering areas," she says.
Kostenki was a focus for human settlement throughout the last ice age, Pryor said: "It’s a huge investment in this particular place in the landscape." His team has some theories as to why. "There’s evidence that there were natural freshwater springs in the area which would have remained liquid throughout the year," he says. "That warmed water would have drawn animals, including mammoth, and in turn attracted humans to the same spot."
While the site raises many intriguing questions, Pryor said that it already tells us something certain about the people who built it.
"This project is giving us a real insight into how our human ancestors adapted to climate change, to the harshest parts of the last glacial cycle, and adapted to use the materials that they had around them," he said. "It’s really a story of survival in the face of adversity."

О попытках возродить российскую науку после многолетнего застоя. В некоторых научно-исследовательских отраслях наметился прогресс, но в целом российская наука пока по-прежнему плохо финансируется и мало цитируется.

In the twilight of a winter’s afternoon on the outskirts of Moscow, a disc-shaped building stands out against dreary tower blocks and largely vacant car parks. This avant-garde architecture - called simply the Disk - hosts the Skolkovo Institute of Science and Technology (Skoltech), a private research centre founded in 2011. Inside its curved, gleaming halls, physicist Denis Kurlov describes how the centre attracted him back to Russia, more than seven years after he left his native country to work abroad.
When Kurlov moved to the Netherlands, he thought he wouldn’t come back. "I didn’t see any place in Russia where I would be able to do research in a stimulating environment and have enough money to make a living." But circumstances have brightened, Kurlov says. When he visited Skoltech’s quantum centre in 2013, Kurlov was surprised to find a modern lab much better equipped than anything he had encountered in his student years in the Russian city of St Petersburg. Last autumn, he joined the centre as a staff scientist working on simulations of quantum effects in ultracold atomic gases. "Something is happening here," he says.
Kurlov isn’t the only scientist sensing change in Russia. After the collapse of the Soviet Union in 1991, Russia’s economy plummeted and tens of thousands of scientists moved abroad or abandoned their careers. The country hasn’t managed to recover its former levels of science funding (after adjusting for inflation, see ‘Spending’) and its researcher workforce has fallen by one-third, although it remains the world’s fifth-largest. But over the past decade, Russian President Vladimir Putin has been promising to reform his country’s languishing science system to make it more competitive and attractive to foreign talent.
In 2018, Putin approved a national research strategy that stretches to 2024. It calls for more money, extra support for early-career scientists, and some 900 new laboratories, including at least 15 world-class research centres with a focus on mathematics, genomics, materials research and robotics. Last year, the government completed a sweeping evaluation of scientific performance at its universities and institutes; it has vowed to modernize equipment in the 300 institutes that made the top quartile. And it says it wants to strengthen previously neglected areas, including climate and environmental research (see ‘Russia’s climate-science ambitions’).
The reality on the ground is mixed. There are patches of promise in some research sectors, but much of Russia’s science remains poorly funded and little-cited; this year, hundreds of Russian-language papers have been retracted because of plagiarism. Researchers still complain about bureaucracy and political interference, and some Russians working abroad say they couldn’t contemplate returning to a country that cannot guarantee its scientists safety and freedom of expression. "I would not want to live and do science in a country where there is continuing government repression of civil society," says Fyodor Kondrashov, a biologist at the Institute of Science and Technology Austria in Klosterneuburg.
But many scientists in Russia do feel the culture is changing for the better, says polymer physicist Alexei Khokhlov, who is a vice-president of the Russian Academy of Sciences (RAS) in Moscow. Academic salaries have risen, and merit-based competition is replacing academic networks built on insider relationships, he says. "Many research positions in Russia were in the past occupied by people who produced little, if any, real science. Now institutes must think about hiring people who will attract grants and write good papers."
The best and the rest
Kurlov and other researchers at Skoltech are set to benefit from a slew of national technology initiatives in the making, including a 5-year, 50-billion rouble (US$790-million) quantum research programme announced last December. Russia is also building large research facilities, including synchrotron light sources in Moscow and Novosibirsk and an ion collider in Dubna.
Another important development was the 2014 establishment of the Russian Science Foundation (RSF) in Moscow. It is the country’s first government-funded agency to award grants only on the basis of competitive, independent peer review - an effort to avoid the cronyism that has dogged Russian science, with much money being given directly to institutes by government ministries.
The RSF has been tasked with improving the quality of Russian science and is developing guidelines for dealing with suspected misconduct as well as for good scientific practice. This includes sensitive areas such as gene editing, for which Russia has attracted worldwide attention.
Last year, Moscow molecular biologist Denis Rebrikov sparked concern when he told Nature he wanted to alter genes in human embryos with the aim of producing gene-edited babies. The RSF does not support that, says its director Alexander Khlunov, although he doesn’t rule out funding "ethically responsible" work involving gene editing in humans in future.
The RSF’s budget is small: at 21 billion roubles this year, an order of magnitude less than that of comparable agencies in Germany or the United States. But by getting overseas scientists to review project proposals and striking bilateral agreements with funders in Germany, Japan, India and other countries, the RSF is boosting the quality of its research, says Khlunov.
One beneficiary of this is physicist Alexander Rodin, whose studies on the composition of the Martian atmosphere are funded by the RSF and the German research-funding agency, DFG. He became a group leader at the Moscow Institute of Science and Technology (MIPT) in 2016. "It was always my dream to start my own lab in Russia," he says. A laser spectrometer he developed will be used in a Mars lander that is set to launch in 2022 as part of the ExoMars programme, which Russia is conducting jointly with the European Space Agency. Rodin says that taking part in international space programmes is crucial for Russia’s identity as a leading space-research nation. "If we refuse to compete in space, we refuse to be Russian," he says.
Rodin and Kurlov’s facilities, however, are unusually well supported in a country where investment in research and development (R&D) is still extremely low. For two decades, R&D spending has hovered at around 1% of gross domestic product (GDP), a proportion much smaller than that of other large science nations. In 2012, Putin set a target for spending to reach 1.77% of GDP by 2018 - but that didn’t happen. Nor did another Putin target: that by 2020, Russia should have 5 universities in the world’s top 100. (It has none.) Current spending plans - if the government follows them - are projected to increase R&D investment only to 1.2% of GDP by 2024, noted an audit of the science sector published this February by the country’s accounts chamber, a parliamentary body that scrutinizes federal finances.
The auditors also pointed out that the bulk of Russia’s total R&D - counting industrial and academic work - is still financed by the state, unlike in most leading science nations, where private companies finance the majority of research. Russian industry’s neglect of R&D is a persistent problem, agrees Grigory Trubnikov, a deputy minister in the Russian ministry for science and higher education. Skoltech is supposed to help improve this - technology firms that move into a science park developing around the institute will enjoy tax incentives and government subsidies. So far, however, this hasn’t led to a major boost in commercial innovation, says Sergei Guriev, an economist at Sciences Po in Paris, who left Russia in 2013.
Papers, please
One of Putin’s targets seems to have borne fruit. After Russia’s scientific output barely rose for two decades, Putin said that its scientists had to be more productive on the global stage. Universities began offering scientists bonuses depending on papers they’d published in international databases, says Khokhlov, the RAS vice-president. The number of such papers with Russian authors subsequently leapt, more than doubling between 2012 and 2018 (see ‘Publication surge’). In December last year, the US National Science Foundation recorded that, in the past decade, Russia has risen from 14th to 7th position in the list of the world’s largest-producing science regions, as measured by publication output.
A closer analysis suggests the story is more complicated. The figures stem, in part, from decisions by international databases to start indexing more local Russian journals, making it unclear how much more work scientists are producing. And although Russia’s scholarly impact measured by citations is slowly rising, it remains far below the world’s average (see ‘Low impact’).
This January, a publishing scandal made international headlines. The RAS announced that its Commission for Countering the Falsification of Scientific Research had revealed widespread plagiarism in papers in Russian-language journals. More than 800 were retracted, in fields covering the humanities, social sciences, medicine and agriculture, with further retractions likely to follow as the investigation continues. "We are getting serious about tackling this problem," says Khokhlov.
The papers involved were in journals that aren’t indexed by international databases and don’t contribute to counts of national output, so were not the type of work that Putin’s target aimed to increase. Still, pressure on Russian scientists to publish more papers to advance their careers might entice misbehaviour, says Mikhail Gelfand, a bioinformatician at the Skoltech Center of Life Sciences, who was involved in the investigation. "Retracting plagiarized papers and shaming the worst offenders is exactly the right thing to do," he says.
International friction
Another feature of Russia’s science record is that its international collaboration rates have dropped sharply over the past decade. In part, that’s because the surge in manuscripts with solely domestic authors has outpaced a small rise in international work (see ‘Collaboration dropping’). But it also points to political tensions. Russia’s annexation of the Crimean peninsula in 2014 dented foreign science relations - particularly those with the United States. Scientists from the two countries collaborate, but official US-Russian science ties have been suspended since 2014, apart from a cooperation agreement signed last year between the RAS and the US National Academies.
Scientists will simply have to live with these realities, says Glenn Schweitzer, a science-diplomacy scholar with the US National Academies. "The value of long-term US-Russian cooperation on global problems is clear," he says. "But science exchanges will continue to be turned off as one country develops policies that conflict with interests of the other." Schweitzer says he’s hopeful the impasse will be temporary, because Russia and the United States did maintain research exchanges during past political conflicts such as the cold war.
Still, Russia is involved in large international research collaborations, including the International Space Station; Europe’s particle-physics laboratory CERN, near Geneva in Switzerland; the international fusion reactor project ITER in France; and in Germany, the European X-ray Free-Electron Laser near Hamburg and the Facility for Antiproton and Ion Research (FAIR), under construction in Darmstadt.
Germany in particular is a key scientific partner for Russia, with almost 300 joint research projects currently under way. Collaborations include research in the geostrategically important Arctic. An ongoing project called MOSAiC (Multidisciplinary Drifting Observatory for the Study of Arctic Climate) - a one-year Arctic research mission involving 300 scientists on board a German research ship locked in sea ice - relies heavily on logistical support from Russian supply vessels, for example.
Red tape and interference
As far back as 2010, Russia’s government launched a programme to entice leading overseas researchers to visit. So far, 272 scientists from 31 countries - 149 foreign scientists and 123 émigré Russian researchers - have received ‘mega-grants’ to set up labs in Russia. The programme could have done more for Russian science had the attached bureaucracy been less excessive, says Gerry Melino, a Italian cancer biologist at the UK Medical Research Council’s Toxicology Unit in Cambridge, who received a $4.9-million grant in 2010 to set up a cytology lab at the Saint Petersburg State Institute of Technology. He spent about three months each year there until the grant ended in 2016.
The students were excellent, Melino says, but local administrators in charge of signing off purchases and promotions were a pain. "How can the system change if you give the money to people who know little or nothing about modern science?" The system is particularly difficult for outside researchers to navigate. "It’s almost impossible for foreigners who don’t speak the language and don’t know the mentality to understand Russian bureaucracy," Melino says.
Buying lab equipment and reagents from foreign suppliers remains a problem, even for scientists who are Russian. "If I work outside our homeland, I get the reagent I need tomorrow," Olga Dontsova, a biochemist at Lomonosov Moscow State University told Putin at a 2018 meeting. "In our country, I have to wait at least three months and pay two or three times more. This is a problem that is forcing young people to prefer to work abroad."
After that discussion, the government reduced the paperwork required for importing lab materials. Common reagents and plastics are now available from Russian delivery companies, but the supply of chemicals that are produced only in the United States or the European Union is still a problem, says Dontsova.
"We still have to wait up to four months until certain antibodies and cell cultures are delivered from abroad," she says. Also, she says, Russian scientists must get advance permission to exchange experimental samples with collaborators outside the country.
Researchers are also worried about political interference. International non-governmental organizations, including conservation and HIV-prevention groups, have been blocked from working in Russia if they receive foreign funding. And in 2015, a private science funder called the Dynasty Foundation, based in Moscow, was closed after the Russian ministry of justice labelled it an undesired ‘foreign agent’.
Late last year, leading scientists with the RAS condemned a police operation at the Lebedev Physical Institute, one of Russia’s leading physics centres. In October, heavily armed police stormed the facility and charged its director, Nikolai Kolachevsky, with assisting in the illegal transfer of items to Germany - specifically, a pair of glass windows allegedly for military use, which had been made by one of the institute’s spin-off companies. The police later dropped criminal charges but are still investigating the case, says Kolachevsky. He rejects accusations of smuggling or other wrongdoing. "It is very unhelpful for a research institute to be described as a place of contraband when my task is to attract young talent," he says.
There are signs that the government is starting to listen to criticism. The country’s science minister, Valery Falkov - who took office last month - began his tenure by scrapping a much-criticized 2019 order that had obliged Russian scientists to get official approval for foreign researchers to visit their institutes. Falkov’s deputy in the science and education ministry, Trubnikov, insists that the tide is turning. "We want to be an open and reliable international science partner with transparent rules," he says.
Conditions for researchers are improving, but the pace of change is too slow, says Kolachevsky. After years of neglect, Russia has lost a generation of scientists. The Lebedev Physical Institute, he says, has an ageing research staff and a paucity of mid-career scientists, and he now needs to develop new leaders from young PhD students. "Too little has happened for too long," he says.
Russia’s Climate-Science Ambitions
After decades of being closed off, Russia is finally opening up to environmental and climate researchers from other countries. At least, that’s the government’s plan; Igor Ganshin, head of international cooperation in the Russian science ministry, points to several projects that promise more collaboration. A planned Russian-German climate-research programme, he says, is in its early stages but should help to spur joint research on topics such as Arctic permafrost melting and carbon transport around Siberia’s rivers and forests. Russia also plans to set up a year-round international research platform on the remote Yamal peninsula in northwestern Siberia. A luxurious US$12-million station called Snezhinka (‘snowflake’), designed by engineers at the Moscow Institute of Physics and Technology and powered by carbon-free hydrogen energy, will open to researchers worldwide in 2022.
Climate and environmental research in the rapidly warming Arctic is a cornerstone of the country’s science strategy. Next year, Russia will chair the Arctic Council, an intergovernmental forum promoting collaboration among eight nations that have territory in the Arctic. Russia will aim to speed up implementation of an agreement to enhance international research in the Arctic, says Ganshin.
But Russian Arctic-research activities go beyond environmental science. They are also driven by military and economic interest in the region’s rich mineral resources. In January, Prime Minister Mikhail Mishustin unveiled a multi-billion-rouble package, including generous tax incentives, for exploration and development of untapped oil and natural-gas resources in the Russian Arctic.
Russia’s economy depends heavily on fossil fuels, and hasn’t yet experienced the climate protests seen in other parts of the world. There is even a sense that warming might benefit the country: a national climate adaptation plan adopted in December last year aims to mitigate the harmful effects of climate change, but also highlights the advantages that warming might have in areas such as energy use, agriculture and navigation in the Arctic Ocean.
Russia has signed the Paris climate agreement, which aims to limit global warming to well below 2 °C above pre-industrial temperatures. But the Climate Action Tracker, a consortium of scientists and policy specialists, has judged the country’s current policies as "critically insufficient" to contribute a fair share to the 2 °C target.
As heatwaves and wild fires have become more common, it is dawning on policymakers and the public that global warming will have an effect in Russia, too, says Anna Romanovskaya, director of the Institute of Global Climate and Ecology in Moscow. Scientists there helped to develop a strategy for low-carbon economic development, which the Russian government is expected to adopt this year, she says.
"The wrong view, orchestrated by the Russian coal and gas industry, that the Paris agreement will kill our economy is losing its appeal," insists Romanovskaya, who is also a member of Russia’s negotiating team in international climate talks.

2020 год объявлен годом российско-китайского научного сотрудничества, однако, по мнению журнала Nature, укрепление связи с Китаем не должно происходить за счет других международных связей.

This week, Russia’s president, Vladimir Putin, asked the courts to allow him to change the nation’s constitution, so it would no longer prevent him from standing for re-election beyond 2024. If he succeeds - and keeps winning elections - Putin could remain president until 2036, more than 35 years after coming to power.
The move to extend Putin’s power has major consequences for Russian society - including science. Putin’s government helped to stabilize research after the chaos of the early 1990s that followed the dissolution of the Soviet Union. Papers authored by Russian scientists more than doubled in the decade between 2006 and 2016. And in 2018, the government allocated 170 billion roubles (US$3 billion at the time) for fundamental research and development, a 25% rise over the 2017 basic-science budget.
But, as we report this week in a News Feature, Russia still has a long way to go before it reaches its full potential in research and innovation. And as the president looks to strengthen his grip on power, some researchers are rightly concerned. Research funding - at 1% of gross domestic product - is far below that of advanced industrialized nations, and promises to increase this have not been kept. Furthermore, bureaucratic and political interference in research is strong.
Coincidentally, China is pursuing closer scientific contacts with Russia, and at a time of economic crisis, these are being welcomed. This year has been designated as the year of Russian - Chinese science cooperation: 800 activities are planned, including joint research in fields ranging from archaeology to artificial intelligence.
In addition to this, Russia is a leading participant in China’s global network of science organizations in the countries that are part of its Belt and Road initiative, known as ANSO (Alliance of International Science Organizations). The organization’s next annual meeting is due to take place in Moscow in May - although this will probably be postponed because of the coronavirus pandemic.
Two years ago, we remarked in these columns how China could help to awaken "the sleeping bear of Russian science". China seems to be doing that, but it is happening as both China and Russia are being isolated by some Western countries. For example, most official US - Russian scientific ties have been suspended since 2014 after Russia’s annexation of the Crimean peninsula. That is a short-sighted strategy. Even at the height of the cold war, researchers from Eastern and Western nations were encouraged to keep collaborations going. It is not too late to change course.

В последнее время Google занимается разработкой улучшенных квантовых процессоров с целью увеличить скорость обработки данных. Для этого был создан квантовый приближенный алгоритм оптимизации QAOA, вызвавший как коммерческий, так и научный интерес в попытках определить его предельные возможности. Исследователям из Сколтеха удалось определить ограничения алгоритма, обнаружив так называемые «дефициты достижимости».

Google is racing to develop quantum-enhanced processors that utilize quantum mechanical effects to one day dramatically increase the speed at which data can be processed.
In the near term, Google has devised new quantum-enhanced algorithms that operate in the presence of realistic noise. The so-called quantum approximate optimization algorithm, or QAOA for short, is the cornerstone of a modern drive towards noise-tolerant quantum-enhanced algorithm development.
The celebrated approach taken by Google in QAOA has sparked vast commercial interest and ignited a global research community to explore novel applications. Yet, little actually remains known about the ultimate performance limitations of Google’s QAOA algorithm.
A team of scientists, hailing from Skoltech’s Deep Quantum Laboratory, took up this contemporary challenge. The all-Skoltech team led by Prof. Jacob Biamonte discovered and quantified what appears to be a fundamental limitation in the wildly adopted approach initiated by Google.
Reporting in Physical Review Letters, the authors detail the discovery of so-called reachability deficits - the authors show how these deficits place a fundamental limitation on the ability of QAOA to even approximate a solution to a problem instance.
The Skoltech team’s findings report a clear limitation of the variational QAOA quantum algorithm. QAOA and other variational quantum algorithms have proven extremely difficult to analyze using known mathematical techniques due to an internal quantum-to-classical feedback process. Namely, a given quantum computation can only run for a fixed amount of time. Inside this fixed time, a fixed number of quantum operations can be executed. QAOA seeks to iteratively utilize these quantum operations by forming a sequence of increasingly optimal approximations to minimize an objective function. The study places new limits on this process.
The authors discovered that QAOA’s ability to approximate optimal solutions for any fixed depth quantum circuit is fundamentally dependent on the problems "density." In the case of the problem called MAX-SAT, the so-called density can be defined as the ratio of the problems constraints to variable count. This is sometimes called clause density.
The authors discovered problem instances of high density whose optimal solutions cannot be approximated with guaranteed success, regardless of the algorithms’ run-time.

Сотрудники Московского физико-технического института и Института общей и неорганической химии имени Н.С.Курнакова РАН помогли реставраторам Третьяковской галереи прояснить вопрос об авторстве одной из работ выдающегося портретиста XVIII века Дмитрия Левицкого. Картина имеет две более поздние вставки, которые и вызывали сомнения. Анализ красочного слоя подтвердил, что все три части написаны Левицким.

Russian researchers from the Moscow Institute of Physics and Technology, Kurnakov Institute of General and Inorganic Chemistry of RAS, and Russia’s famed Tretyakov Gallery have conducted a comprehensive preconservation study of "The Portrait of F.P. Makerovsky in a Masquerade Costume" (1789) by the Russian painter Dmitry Levitsky. The paper was published in the journal Heritage Science.
The portrait analyzed in the study is one of the masterpieces of the renowned painter’s mature period and a rare example of a children’s dress-up portrait in Russian art. However, rough restoration interventions of a century ago, thick layers of old yellowed varnish, and damage to the paint layer of unknown origin distorted the aesthetic perception of the image. The conservator, Tatiana Seregina, faced the difficult task of bringing the portrait as close to its original state as possible today, without affecting the painter’s work.
"Our laboratory and the gallery’s research team maintain a long-standing methodological collaboration, which manifested itself in a 2017 agreement between MIPT and the Tretyakov Gallery, with the support of its chief curator Tatiana Gorodkova," said Viktor Ivanov, the head of the Center for Functional Materials Testing at MIPT. "Under that agreement, we jointly develop approaches for comprehensive studies of artworks using modern methods for local analysis of materials and nanomaterials. The methodological expertise that we accumulated enabled us to participate in a preconservation study of the painting by Dmitry Levitsky and establish the unity of the paint layers across the entire canvas."
The research team comprised numerous physicists, chemists, art specialists, and conservators from MIPT, IGIC RAS, and the State Tretyakov Gallery.
Besides enabling more grounded decisions regarding the conservation techniques to be used, the analysis of the art materials also resolved a long-standing mystery. Levitsky’s painting consists of three fragments, and while there were never any doubts concerning the authorship of the main part, it remained unknown when the two horizontal extension pieces with the figure from the knees down had been sewn to the canvas. While the extension pieces are visible in early-20th-century photographs, there were reservations about the earlier period in the painting’s history, because of a distinct structure of the seams connecting the three fragments: While the upper seam is very neat, the lower one is much coarser.
"The last time the portrait underwent conservation was in 1914," study co-author Nikolay Simonenko from IGIC RAS and MIPT said. "We conducted a comprehensive preconservation analysis of art materials composition. This allowed us to establish that the extension pieces were indeed painted by Levitsky."
Painter in a hurry?
By analyzing the ground layers, the team first revealed a distinction between the main canvas and the extension pieces. The two layers of ground, customarily used by the painter, were only found in the main canvas. However, a closer look revealed the structure and composition of the ground in the two extensions to be alike. It also proved similar to the lower of the two ground layers of the main canvas.
The authors of the paper suggest that the painter might have had more time at the outset to thoroughly prepare the canvas. It is likely, the researchers hypothesize, that Levitsky’s concept of the painting evolved as the work progressed, necessitating a bigger canvas. To accommodate his new vision, the painter first added one extension piece and then another.
Malachite pigment
By examining the paint layers, the team could show their similar composition across the entire painting, including the two extension pieces. Specifically, the green pigment is present in each of the three fragments and has a common nature: Infrared spectroscopy revealed it was malachite.
Interestingly, none of the other 10 or so analytic techniques used in the study could identify malachite, although elemental analysis did provide an indirect confirmation by detecting copper in the green paint. This is why the researchers had to employ such a wide range of tools in their study.
The common origin of the two extension pieces was also confirmed by the analysis of the brown pigment, which involved infrared and Raman spectroscopy, and scanning electron microscopy combined with energy dispersive X-ray spectroscopy.
By investigating the painted layer, the team established that it belonged to Levitsky in its entirety, confirming the hypothesis that a single artistic process united all three parts of the canvas.
Fine arts and hard sciences
In a research project like this, the chemists and physicists are after great detail in the results, which may in part go against the wish of the museum workers and conservators to preserve the work of art fully intact.
"In my opinion, the presence of art historians, chemists, and physicists in one team was key to the success of this endeavor," said Ivan Volkov, a chief researcher at the MIPT lab involved in the study. "We held regular meetings featuring both the Tretyakov Gallery team and us, materials scientists. We had to slowly work out a common language, but it was worth it. There was also an arrangement for the sampling methods and tools to be approved by the gallery staff."
With no room for error, the team needed to be very careful in taking samples, and extract maximum information from each of them. The researchers sought a middle ground to draw information from the portrait without damaging it. For example, some of the samples were taken from the edges of the painting.
New discoveries
This is the first time such a detailed and comprehensive study of a painting by Levitsky has been carried out. According to art specialists from the Tretyakov Gallery, the study has not only been important for preparing the conservation task, but also expanded the understanding of Levitsky’s oeuvre and the late 18th-century art practice in Russia.
Now that the methodology has been developed and successfully tested, it can be applied to other works. Meanwhile, the conservation of Makerovsky’s portrait is in its final stages, and it will soon return to the main exhibition. The conservation began long before the publication in Heritage Science and lasted about a year and a half.

Российская исследовательская группа опубликовала фундаментальный обзор, посвященный современным технологиям диагностики вирусных инфекций. Основной проблемой является то, что системы тестирования ориентированы на узкий спектр вирусов, в результате чего большинство вирусов не обнаруживаются и не исследуются.

In a recently published fundamental review dedicated to the diagnostics of viral infections, a Russian research team featuring MIPT researchers was the first to systematically describe and summarize the cutting-edge technologies in the rapidly developing field of genetics. A number of new effective methods of virus detection have been developed over the past few years, including those targeted at unknown pathogens. The authors described the so-called high-throughput next-generation sequencing as a potent new approach. The method promises to revolutionize the detection and analysis of new pathogenic viruses, but it will be at least several years until it is introduced into mainstream clinical practice.
In response to the rapid spread of the COVID-19 pandemic, an authoritative global scientific journal, aptly named Viruses, published a fundamental review of problems related to identifying and studying emerging pathogens, such as the notorious coronavirus.
"There are, by various statistical estimations, over 320,000 various viruses infecting mammals. But up to date, less than 1% of this vast multitude has been studied." - Kamil Khafizov, a researcher at MIPT's Historical Genetics, Radiocarbon Analysis and Applied Physics Lab and one of the review's authors.
Most viruses, including those that cause respiratory, digestive, and other diseases in humans, remain unresearched and thus almost undetectable. The reason behind this is the narrow spectrum of viruses that the modern testing systems are designed to target.
"Metaphorically, we are attempting to look at a vast sea of threats through the eye of a needle," the authors write in the review. Among other things, they explore the shortcomings of the polymerase chain reaction method. This essential technique for microorganism molecular testing fails to identify poorly explored viruses, and this constitutes one of the key problems in modern virology.
There are, however, new methods that may potentially solve the issues of detecting and identifying new microorganisms, and the review explores these approaches. The authors consider next-generation sequencing (NGS) to be the most promising. Also known as high-throughput sequencing, it enables the analysis of multiple DNA molecules in parallel, be it a set of samples, different regions of the same genome, or both.
"Efficient mathematical algorithms are a key part of the method," says Alina Matsvay, MIPT doctoral student and the review's correspondent author. "They allow researchers to compare the genome of an unknown virus against all available references of viral genomes, and predict all of its possible characteristics, including its pathogenic potential."
The key shortcomings of NGS include the high cost of equipment and reagents needed for running such tests and the lengthy sample preparation, sequencing, and data analysis processes. These limitations, combined with high lab personnel qualification requirements, prevent the method from being widely integrated in the mainstream clinical practice. Nevertheless, the cost of the technology goes down with each year, while its speed, accuracy, and efficiency keep growing.
Khafizov noted that the coronavirus pandemic has demonstrated the importance of NGS methods for identifying new pathogens in clinical samples and studying the molecular mechanisms of virus transmission from animals to humans. The technology may be certified for use in health care in the immediate future.
Apart from the MIPT scientists, the authors of the fundamental review also included researchers from the Center of Strategic Planning of Russia's Ministry of Health, I.M. Sechenov First Moscow State Medical University, and Pasteur Institute in St. Petersburg.

Основным способом восприятия магнитного поля у птиц считаются фотохимические реакции в светочувствительном белке криптохроме в сетчатке глаз. Орнитологи и физики из Санкт-Петербургского университета вместе с коллегами из Института эволюционной физиологии и биохимии имени И.М.Сеченова РАН и Зоологического института РАН проверили эту теорию, создав миниатюрное электромагнитное устройство (OMF), локально воздействующее на глаза птиц. Однако никакого влияния на способность ориентироваться устройство не оказало. Когда же в экспериментальной камере включали большое устройство OMF, действующее на все тело птиц, они демонстрировали явную дезориентацию.

Ornithologists and physicists from St Petersburg University have conducted an interdisciplinary study together with colleagues from Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences and the Biological Station Rybachy of the Zoological Institute of the Russian Academy of Sciences. They have created a micro device, weighing less than a gram, which enables them to disrupt locally the avian magnetic compass. The scientists have discovered that magnetoreception in birds is unlikely to be associated with the light-sensitive protein cryptochrome in the retinas of their eyes, though photochemical reactions in cryptochrome have been so far considered to be the primary biophysical mechanism behind the magnetic sense of birds.
At present, researchers are puzzled by the mechanism of avian magnetic orientation, which allows migratory birds to solve the complex tasks of moving between distant breeding and wintering grounds. The existence of a magnetic compass system in birds has been well documented, but the sensory mechanism and its location still remain unknown. What is known is that birds use multiple sources of directional information for their navigation: the sun, stars, landscape, smells, as well as parameters of the Earth's geomagnetic field. Birds can use the geomegnetic field to maintain the flight direction (magnetic compass) and, possibly, to determine their location (magnetic map). It was also established that the avian magnetic compass can be disrupted if the whole body of the bird is exposed to a weak oscillating magnetic field (OMF) in the megahertz range. Furthermore, in 2018, an international team of researchers, which included scientists from St Petersburg University, found that magnetic map information is transmitted to the brain of the bird through the ophthalmic branches of the trigeminal nerve. Thus, the functions and certain neural pathways are known, yet the receptor itself has still not been found.
According to one of the theories explaining the unique ability of migratory birds, the most probable magnetoreceptors are molecules of a photosensitive protein, the cryptochrome. These are located in the retina of the bird's eye. The outcome of the photochemical reactions inside the magnetically sensitive protein depends on intensity and direction of the magnetic field. Some researchers suggest that the cryptochromes in birds' eyes give them an ability to 'see' the Earth's magnetic fields. To check whether the avian magnetic compass is really embedded in the visual system, the researchers from St Petersburg University decided to apply OMF locally to the bird's eyes. Theoretically, this should have disrupted the bird's orientation.
"We have developed miniaturised devices, each weighing just 0.95 grams and comprising a magnetic coil and a high-frequency generator fed from watch batteries," explained Kirill Kavokin, Leading Scientist of the I.N. Uraltsev Spin Optics Laboratory at St Petersburg State University. "Since the coils are very small, the magnetic field can be applied locally only to the bird's eyes. It was a challenge to construct such a device. Besides, we spent a lot of time selecting a non-toxic adhesive that would be safe for birds and provide reliable bonding. This turned out to be an eyelash glue."
Twenty-two Garden warblers were equipped with portable devices, with the magnetic coil attached to the bird's head. The Garden warbler is a widespread small bird that breeds in most of Europe and spends the winter in Africa. The experimental birds were captured during the autumn migration at the Biological Station Rybachy on the Courish Spit, Kaliningrad region, Russia. After a series of experiments, it was determined that the birds with portable devices attached, both in 'on' and 'off' state, behave the same way. The birds were tested in round arenas placed inside a screened and grounded non-magnetic chamber with artificial nocturnal lighting by green LEDs. Under these conditions, the only orientation cue available to the experimental birds during the tests was the geomagnetic field. The birds, however, were not disoriented and showed the seasonally appropriate migratory direction - southwest. On the contrary, when placed in an OMF generated by large stationary coils in control experiments, the birds demonstrated clear disorientation.
"Our findings cast doubt on the prevailing photochemical theory of the magnetic compass of birds. They point to the existence of other components of the avian magnetoreception system that are sensitive to OMFs. These findings challenge the existing ideas about the biophysics and neurophysiology of magnetoreception", said Julia Bojarinova, one of the leading authors of the research, Associate Professor of the Department of Vertebrate Zoology at St Petersburg University.
In further experiments, the scientists seek to explore other places on the bird's body where the compass receptor may 'hide itself.' According to available data, such a receptor might be situated either in the upper beak, or in the lagena - part of the bird's inner ear. To test new theories, experimenters will be able to utilise the developed miniaturised devices - only slight modifications of the magnetic coils will be required.
"At present, our interest is mainly fundamental. We are driven by curiosity, as the magnetic compass of birds remains the unsolved puzzle," noted Kirill Kavokin. "Nonetheless, there is a chance that the solution of this fundamental problem will enable the creation of new satellite-free navigation systems." After all, birds always know where to fly, and they do not need satellites for navigation."

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