|Российская наука и мир|
(по материалам зарубежной электронной прессы)
Российские физики модернизировали «ядерную батарейку», которая генерирует электроэнергию посредством бета-распада изотопа никеля-63. Предложенный метод позволяет почти в 10 раз увеличить удельную мощность «батарейки» за счет алмазных преобразователей на основе барьера Шоттки.
Russian scientists from the Moscow Institute of Physics and Technology (MIPT), the Technological Institute for Superhard and Novel Carbon Materials (TISNCM), and the National University of Science and Technology MISIS have upgraded the design of a nuclear battery that produces power from the beta decay of nickel-63, a radioactive isotope.
The innovative battery prototype developed by the researchers has the ability to pack nearly 3300 mW-hours of energy per gram, which is greater when compared to any other nuclear battery based on nickel-63, and 10 times higher when compared to the specific energy of commercial chemical cells. The study has been reported in the Diamond and Related Materials journal.
In normal batteries that power toys, flashlights, clocks, and other compact autonomous electrical devices, the energy of the well-known redox chemical reactions is used. Here, transfer of electrons from one electrode to the other occurs through an electrolyte. This results in a potential difference between both the electrodes.
Upon connecting the two battery terminals by a conductor, the potential difference is eliminated when the flow of electrons starts, thus producing an electric current. Chemical batteries, also called galvanic cells, possess high power density, or the ratio of the volume of the battery to the power of the produced current.
Yet, chemical cells tend to discharge within a comparatively short period of time, restricting their usage in autonomous devices. Although some of these batteries, known as accumulators, are rechargeable, they have to be replaced for charging. This could be risky, such as in a cardiac pacemaker, or even impossible, if the battery is used for powering a spacecraft.
Nuclear Batteries: History
Luckily, chemical reactions are just one among many probable sources of electric current. In 1913, Henry Moseley was the first to invent a power generator based on radioactive decay. In his nuclear battery, a glass sphere silvered on the inside was equipped with a radium emitter positioned at the center on an isolated electrode.
Electrons emitted as a result of the beta decay of radium led to a potential difference between the central electrode and the silver film. Yet, the device's idle voltage was very high, of the order of tens of kilovolts, and the current was very low for practical applications.
In 1953, Paul Rappaport hypothesized the application of semiconducting materials for transforming the energy of beta decay into electric power. Beta particles, positrons and electrons, emitted from a radioactive source have the ability to ionize atoms of a semiconductor, producing uncompensated charge carriers.
When a static field exists in a p-n structure, the charges flow in a single direction, leading to electric current generation. Batteries powered by beta decay were termed betavoltaics. The main benefit of betavoltaic cells, when compared to galvanic cells, is their longer life: Since the half-lives of the radioactive isotopes used in nuclear batteries range from tens to hundreds of years, their power output stays almost constant for a very long time.
Sadly, betavoltaic cells have a considerably lower power density when compared to galvanic cells. Without regard to this, betavoltaics were indeed used in the 1970s to power cardiac pacemakers, before being withdrawn to make way for the low-cost lithium-ion batteries, although the lithium-ion batteries have shorter lifetimes.
Betavoltaic power sources are not the same as radioisotope thermoelectric generators (RTGs), which are also known as nuclear batteries yet operate on a distinctive principle. In thermoelectric cells, thermocouples are used for converting the heat released by radioactive decay into electric power. RTGs have limited efficiency, which is dependent on temperature.
However, due to their longer lifetimes and comparatively simple design, thermoelectric power sources are largely used for powering spacecraft such as the New Horizons probe and Mars rover Curiosity. Earlier, RTGs were used on unmanned remote facilities such as automatic weather stations and lighthouses. Over time, this practice was given up since it was hard to recycle used radioactive fuel, which eventually leaked into the environment.
Ten Times More Power
A team of researchers headed by Vladimir Blank, the director of TISNCM and chair of nanostructure physics and chemistry at MIPT, proposed a method for increasing the power density of a nuclear battery by nearly 10 times.
The physicists designed and constructed a betavoltaic battery with nickel-63 as the radiation source and Schottky barrier-based diamond diodes for energy conversion. With the prototype battery, they were able to realize an output power of nearly 1 μW, where the power density per cubic centimeter was 10 1 μW, which is adequate for a modern artificial pacemaker. Since the half-life of Nickel-63 is 100 years, the battery packs nearly 3300 mW-hours of power per gram, which is 10 times more when compared to electrochemical cells.
In the nuclear battery prototype, 200 diamond converters were interlaid with nickel-63 and stable nickel foil layers. The amount of power produced by the converter is based on the thickness of the nickel foil and the converter itself.
This is because both have an impact on the number of beta particles absorbed. At present, the available prototypes of nuclear batteries are poorly upgraded due to their excessive volumes. In case the thickness of the beta radiation source is very high, the electrons emitted by it cannot escape from it. This effect is termed self-absorption.
Yet, when the thickness of the source is reduced, the number of atoms that undergo beta decay in a given unit of time is proportionally minimized. Similar reasoning is applicable to the thickness of the converter.
The aim of the team was to increase the power density of their nickel-63 battery. To achieve this, the passage of electrons through the beta source and the converters was numerically simulated. It was observed that the nickel-63 source is highly effective when its thickness is 2 μm, and the optimal thickness of the converter depending on Schottky barrier diamond diodes is about 10 μm.
The major technological problem was the fabrication of more number of diamond conversion cells that have a complex internal structure. The thickness of each converter was of the order of only tens of micrometers, such as a plastic bag in a supermarket.
Traditional mechanical and ionic methods of diamond thinning were not appropriate for this task. The scientists from TISNCM and MIPT devised a distinctive technology for fabricating thin diamond plates on a diamond substrate and splitting them off to enable mass-production of ultrathin converters.
The researchers used 20 thick boron-doped diamond crystal plates as the substrate. These plates were grown with the help of the temperature gradient method under high pressure. Ion implantation was employed to produce a 100-nm-thick defective, "damaged" layer in the substrate at the depth of around 700 nm.
A 15-μm-thick boron-doped diamond film was formed on top of this layer with the help of chemical vapor deposition. Then, the substrate was subjected to high-temperature annealing to initiate graphitization of the buried defective layer and recover the top diamond layer.
The damaged layer was removed through electrochemical etching. Once the defective layer was separated through etching, ohmic and Schottky contacts were fitted on the semi-finished converter.
Upon repeating the aforementioned operations, the loss of substrate thickness aggregated to not more than 1 μm per cycle. In total, 200 converters were grown on 20 substrates. This innovative technology is significant from an economic point of view because the cost of high-quality diamond substrates is very high, and hence, it would be impossible to mass-produce converters by substrate thinning.
All converters were connected in parallel in a stack. The technology for rolling 2-μm-thick nickel foil was devised at the Research Institute and Scientific Industrial Association LUCH. Epoxy was used to seal the battery.
The short-circuit current and the open-circuit voltage of the prototype battery are 1.27 μA and 1.02 V, respectively. At 0.92 volts, the maximum output power of 0.93 microwatts is realized. This power output is in accordance with a specific power of around 3300 mW-hours per gram, which is 10 times more than that observed in commercial chemical cells or the earlier nickel-63 nuclear battery designed at TISNCM.
In 2016, Russian scientists from MISIS had already introduced a prototype betavoltaic battery based on nickel-63. One more working prototype, which was developed at TISNCM and LUCH and demonstrated at the Atomexpo 2017, had a useful volume of 1.5 cm3.
The major drawback in commercializing nuclear batteries in Russia is the lack of nickel-63 production and enrichment facilities. Yet, plans have been proposed to launch the production of nickel-63 on an industrial scale by mid-2020s.
An alternative radioisotope can also be used in nuclear batteries: Radioactive carbon-14 can be used to make diamond converters since it has an exceptionally long half-life of 5700 years. Physicists from the University of Bristol previously reported a study on such generators.
Nuclear Batteries: Prospects
The study reported here could find prospective applications in medical applications. The size of a majority of the sophisticated cardiac pacemakers is more than 10 cm3 and they need around 10 μW of power.
This indicates that it is possible to use the innovative nuclear battery to power up these devices without any major changes to their size and design. "Perpetual pacemakers", with batteries that need not be serviced or replaced, would enhance patients' quality of life.
Compact nuclear batteries could also prove highly beneficial, in general, for the space industry. Specifically, there is a demand for autonomous wireless external sensors and memory chips including integrated power supply systems for spacecraft.
Diamond is one of the most radiation-proof semiconductors. Due to its large bandgap, it has the ability to work in a broad range of temperatures, rendering it the perfect material for nuclear batteries that power spacecraft.
The team has proposed to continue its research on nuclear batteries. The researchers have recognized various lines of inquiry that should be sought.
First, battery power can be proportionally increased by enriching nickel-63 in the radiation source.
Second, voltage can be boosted and hence the battery's power output can be increased at least by a factor of three by developing a diamond p-i-n structure with a controlled doping profile.
Third, the number of nickel-63 atoms in each converter can be increased by increasing the surface area of the converter.
According to Vladimir Blank, TISNCM Director, who is also chair of nanostructure physics and chemistry at MIPT: "The results so far are already quite remarkable and can be applied in medicine and space technology, but we are planning to do more. In the recent years, our institute has been rather successful in the synthesis of high-quality doped diamonds, particularly those with n-type conductivity. We have decent capabilities for high-quality diamond synthesis, so we are planning to utilize the unique properties of this material for creating new radiation-proof electronic components and designing novel electronic and optical devices".
AZoNetwork, © 2000-2018.
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Ars Technica / 6/7/2018
Russia may lack the funds to compete with SpaceX's Falcon 9 rocket
"The development of new boosters is doubtful from a practical perspective".
В ближайшие годы «Роскосмос» может столкнуться с заметным сокращением бюджета. По некоторым сведениям, дефицит финансирования составит около 150 мрд рублей. Это сделает невозможным создание новой ракеты-носителя среднего класса «Союз-5», задуманной как конкурент американской Falcon 9, а также разработку сверхтяжелого носителя «Ангара».
The Russian space program's budget process is not particularly transparent to outsiders, but it does appear likely that Roscosmos will face cuts in the coming years. According to Sputnik, a Russian government-controlled news agency, the Roscosmos state corporation will likely to suffer funding shortages amounting to 150 billion rubles (more than $2 billion) in the next three years, from 2019 to 2021.
The consequences of these cuts could be severe for Russia's much-vaunted launch industry. In particular, the reduced budget could forestall a rocket development project intended to compete with SpaceX's Falcon 9 rocket and a new super-heavy lift booster.
One expert observer of the Russian space program, Ivan Moiseev, the scientific leader of the Russian Space Policy Institute, says this is the case. Cuts in the Roscosmos budget will make it impossible to develop the new Soyuz-5 medium-lift booster, the Falcon 9 competitor, as well as imperil further development of a heavy-lift variant of the Russian Angara rocket.
"One can say that the current plan for an ultra-heavy booster is unnecessary because there is no payload or mission for it, and even the draft design has already cost a billion (rubles)", Moiseev told the Russian publication Lenta.RU. "Additionally, the development of new boosters is doubtful from a practical perspective, because the number of payloads we (Russia) will be lofting is fairly well known, and it is not growing with any stability".
Russia recently completed preliminary design work on the Soyuz-5 rocket, a medium-lift booster, with a first stage powered by RD-171 engines that will burn kerosene fuel. This new efficient booster, Russian officials felt, could replace the existing Soyuz rocket that carries cosmonauts and astronauts into space while competing with SpaceX on price for commercial payloads.
If fully funded, the Soyuz-5 could be ready for service by 2022, but budget cuts will preclude that, Moiseev said. Any delays to the project will probably prove fatal, as SpaceX's Falcon 9 rocket is likely to see diminished costs over time as the company continues to improve the booster's reusability. In other words, even if the Soyuz-5 rocket is competitive on paper with the Falcon 9 now, it is unlikely to be so four years from now.
As for the heavier lift Angara rocket, Moiseev said there is little need to build the bigger rocket at this time because Russia has no specific payloads for it. "We only need to build the new booster if there is a specific mission to launch something the older boosters aren't capable of lifting", Moiseev said. Indeed, the looming budget cuts suggest that such missions could themselves not be funded at this time.
The biggest space news out of Russia in the last few weeks has been confirmation that former deputy prime minister Dmitry Rogozin, who has been critical of NASA and been sanctioned by the United States, will now head Roscosmos. Very quickly, he will have to confront these budgetary issues and likely make decisions about Russian rocket development. He will need to be creative, as Vladimir Putin has just said, "We need to restore our leadership in space launches".
© 2018 Condé Nast. All rights reserved.
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Лауреатами премии «Глобальная энергия» в этом году стали российский физик, академик РАН Сергей Алексеенко (директор Института теплофизики СО РАН в 1997-2016) - за разработки в области теплоэнергетики, которые позволяют создавать современное энергосберегающее оборудование, и австралийский ученый, профессор Университета Нового Южного Уэльса Мартин Грин - за технологии в фотовольтаике, повышающие экономичность и эффективность солнечных элементов.
The names of the Global Energy Prize laureates were announced during the official press conference in Moscow on June 6. In 2018, the prestigious award goes to scientists from Russia and Australia. Russian academician Sergey Alekseenko will be awarded for developments in the field of heat power engineering, which allow creating modern energy-saving equipment while Professor Martin Green will be recognized for technologies in photovoltaics increasing cost effectiveness and efficiency of solar cells. The solemn Award Ceremony will be held in October within the framework of the Russian Energy Week International Forum. The laureates of 2018 will receive golden medals, diplomas, honorary lapel badges and will share RUB 39 000 000 (approximately $ 650 000).
The laureates of 2018 were determined on June 5, 2018 at the Global Energy Prize International Award Committee meeting but the information remained a secret until the last moment. The Global Energy Prize International Award Committee consists of 20 experts from 13 countries. Famous British scientist, the Nobel Prize winner Rodney John Allam, chairs it. During the official press conference, he summed up the results of the XVI nomination cycle and noted that 44 scientists from 14 countries competed for the award. Talking about main areas researchers' focus, he emphasized that the largest number of nominations referred to the renewable energy sector (34,09%); while exploration, production, transportation and processing of energy resources hold the second place (15.91%). Nuclear power industry (13.64%) closed the top three most popular fields. Traditionally, the geography of the contest is impressive: scientists from Europe, North America, Asia and Oceania competed for the victory. Whereby, the majority of nominees (56%) are representatives of European countries.
Adding details about the prize, the Global Energy Prize International Award Committee member, the Director-General of the International Renewable Energy Agency (IRENA) Adnan Amin stressed the contribution of the Global Energy Prize to the creation of the sustainable future for the benefit of all humanity and the commitment of Russia to use its energy potential in the field of RES.
Rae Kwon Chung (Korea), member of the Global Energy Prize International Award Committee, Adviser to the Chair of UN Secretary-General's High-level Expert and Leaders Panel (HELP) on water and disasters, spoke about the importance of scientific cooperation that has no borders. It was he who brought the happy news to new laureates via the phone call, which was broadcast to the whole audience.
The first scientist who found out about his victory was RAS academician Sergey Alekseenko (Russia), an expert in thermophysics, energy and energy saving. The prize is awarded to him for the development of thermophysical foundations of the modern power and energy saving equipment creation, which allow developing ecologically safe thermal power plants (through modeling of combustion of gas, coal and liquid fuel). They are also used in the development of the new types of burners, methods for thermal processing of solid domestic waste to generate thermal energy, as well as modeling of natural gas liquefaction processes, development of thermal and hydraulic safety standards for nuclear power plants, etc. Besides that Sergey Alekseenko is the initiator of the wide application of petrothermal energy (Earth's internal heat). The scientist is convinced that this energy will ensure the energy needs of humanity forever.
For the second year in a row, the experts of the Global Energy Prize International Award Committee recognize solar technologies. Martin Green (Australia) will be awarded the Global Energy Prize for research, developments and educational activities in the field of photovoltaics. The sales of the systems containing the PERC solar cells invented by Martin Green exceeded $4 billion by the end of 2016. According to Bloomberg New Energy Finance predictions, the total sales of solar cells using his technology will exceed 1 trillion USD by 2040. PERC elements are already becoming the commercial standard all over the world. According to forecasts, they will save at least 750 million dollars in power production costs over the next decade in Australia alone.
The importance of such practical application of technologies and the applied role of laureates' developments was emphasized by Oleg Budargin, Vice-Chairman of the World Energy Council, member of the Board of Trustees of the Global Energy Association. He also spoke about a new technological cycle in the energy sector, in which the role of science, the Global Energy Prize laureates and young scientists is crucial. "Science and scientists today are at the forefront of entering the new technological cycle. This cycle poses an important task - improving the quality of life of mankind. Moreover, it is science that is called upon to become a locomotive for new education and new productions" the expert shared.
As a recall, the solemn Global Energy Prize Award Ceremony will be held within the framework of the Russian Energy Week International Forum. President or a person on his behalf will award the prize.
©The Global Energy Association, 2002-2018 All rights reserved.
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Ученые НИТУ «МИСиС» и Дагестанского госуниверситета провели сканирование методом мюонной радиографии подземного помещения, обнаруженного на территории крепости Нарын-кала в Дербенте - изучить его путем обычных раскопок было затруднительно. Сооружение имеет странную крестообразную форму и, по одной из гипотез, может оказаться христианским храмом IV века, древнейшим на территории России. Сканирование позволит создать 3D-модель сооружения и судить о его назначении более точно.
NUST MISIS scientists, in collaboration with colleagues from both the P.N. Lebedev Physical Institute of the Russian Academy of Sciences and Dagestan State University, have conducted an experiment with the help of muon radiography method (a modern method of scanning the internal structure of substances) that could turn out to be substantial. The research group non-invasively scanned the hidden space underground the northwestern part of the Naryn-Kala fortress (Derbent). The team is currently processing the information from the sensors.
The 12-meter section is almost completely hidden underground, and only a piece of a dilapidated dome is visible from the surface. The structure dates back to around the year 300 A.D. Until recently, people in the area believed this was just an underground reservoir. However, recent archeological research suggests this structure is the oldest Christian Temple in modern-day Russian. The Arabs controlled much of this area after their capture of Derbent (around 700 A.D.). Experts believe this to be a Christian Temple due to the cross-section of the building, traces of immured entrances, and the location of the structure's walls.
Not all archeologists agree with the last interpretation. It is difficult to settle their dispute with traditional methods because the Naryn-Kala fortress is a UNESCO cultural heritage site. It is not clear how the walls of the building, which have been exposed to water for quite long, will act when taken from the ground.
"A group of scientists led by Professor Natalya Polukhina, a leading expert at NUST MISIS, and including researchers from the P.N. Lebedev Physical Institute of the Russian Academy of Sciences, has applied the method of muon radiography to an ancient structure located in the territory of the Derbent Naryn-Kala fortress. The method allows us to 'illuminate' object with a size of a few meters to two kilometers. Professor Polukhina, who is one of the world`s greatest specialists in this method, is now supervising the installation of muon sensors in the new SHiP experiment on the Large Hadron Collider, in which NUST MISIS is participating jointly with 40 world leading universities", said Alevtina Chernikova, Rector of NUST MISIS.
The muon radiography method has already proven its effectiveness - with its help researchers have already found a hidden room in the Pyramid of Cheops.
The so-called track detectors, which can not only illuminate the muons falling on them but also determine the direction of their movement with high accuracy, have been developed based on muon sensors. By deciphering the readings from these sensors it is possible to make a three-dimensional image of a variety of objects. By piecing these individual scans together, a finished product map of mountains and caves would be incredibly accurate. The scans can also determine the boundaries of different rocks and their density.
The essence of the muon radiography method is to fix the muon flux density. Muons are unstable elementary particles with a negative electric charge that are born in dense layers of the atmosphere due to the decay of protons flying from space. Muons "die" quickly, managing, however, to go through the whole atmosphere of the earth during their life (10 thousand muons reach every square meter of the Earth's surface every minute), and even to reach 8.5 kilometers under water or 2 kilometers into the Earth's crust.
The denser the substance-the faster the flow of muons (and the faster they weaken and die as well). Therefore, if we put a solid object between the "space" and the detector, then the detector will eventually reveal the object's silhouette. If there are cavities in the object, they will also become visible as muons flying through them overcome a smaller layer of mass.
The preliminary analysis of the fortress conducted by specialists on topographic maps from NUST MISIS and the P.N. Lebedev Physical Institute of the Russian Academy of Sciences allows researchers to suggest that in this case, the technique is effective - the sensors can be located to completely scan the object. In addition, the density of the stone and the surrounding rock is more than 5%, which will also allow researchers to distinguish the exterior of the building.
Copyright © 2018 by the American Association for the Advancement of Science (AAAS).
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Палеонтологи из Вятского палеонтологического музея и Музея естественных наук Северной Каролины описали обнаруженные в Кировской области окаменевшие останки двух ранее неизвестных видов хищников пермского периода. Животные относятся к тероцефалам и горгонопсам, подоотрядам терапсид, сочетающих признаки рептилий и млекопитающих. Большинство терапсид вымерло во время так называемой пермской катастрофы около 252 млн лет назад.
Fossils representing two new species of saber-toothed prehistoric predators have been described by researchers from the North Carolina Museum of Natural Sciences (Raleigh, USA) and the Vyatka Paleontological Museum (Kirov, Russia). These new species improve the scientists' understanding of an important interval in the early evolution of mammals - a time, between mass extinctions, when the roles of certain carnivores changed drastically.
Living mammals are descended from a group of animals called therapsids, a diverse assemblage of "protomammals" that dominated terrestrial ecosystems in the Permian Period (~299-252 million years ago), millions of years before the earliest dinosaurs. These protomammals included tusked herbivores, burrowing insectivores, and saber-toothed predators. The vast majority of Permian therapsids have been found in the Karoo Basin of South Africa, and as a result, the South African record has played an outsized role influencing scientists' understanding of protomammal evolution. Because of this, therapsid fossils from outside of South Africa are extremely important, allowing scientists to discern whether observed events in the protomammal fossil record represent global or merely regional patterns.
Recent expeditions by the Vyatka Paleontological Museum have collected a wealth of spectacularly-preserved Permian fossils near the town of Kotelnich along the Vyatka River in European Russia. These fossil discoveries include the remains of two previously unknown species of predatory protomammals, newly described in the journal PeerJ by Christian Kammerer of the North Carolina Museum of Natural Sciences and Vladimir Masyutin of the Vyatka Paleontological Museum. The first of the two new species, Gorynychus masyutinae, was a wolf-sized carnivore representing the largest predator in the Kotelnich fauna. The second new species, Nochnitsa geminidens, was a smaller, long-snouted carnivore with needle-like teeth. Gorynychus belongs to a subgroup of protomammals called therocephalians ("beast heads"), whereas Nochnitsa belongs to a different subgroup called gorgonopsians ("gorgon faces").
Both new species are named after legendary monsters from Russian folklore, befitting their menacing appearances. Gorynychus is named after Zmey Gorynych, a three-headed dragon, and Nochnitsa is named after a malevolent nocturnal spirit. (Based on their relatively large eye sockets, it is likely that Nochnitsa and its relatives were nocturnal).
Gorynychus and Nochnitsa improve scientists' understanding of ecosystem reorganization after the mid-Permian extinction (260 mya). Although not as well-known as the more devastating end-Permian mass extinction (252 mya, which nearly wiped out protomammals), the mid-Permian mass extinction also played a major role in shaping the course of protomammal evolution. In typical late Permian ecosystems, the top predators were giant (tiger-sized), saber-toothed gorgonopsians and therocephalians were generally small insectivores. In mid-Permian ecosystems, by contrast, these roles are reversed. At Kotelnich, the saber-toothed top predator Gorynychus is a therocephalian and the only gorgonopsians are much smaller animals.
"In between these extinctions, there was a complete flip-flop in what roles these carnivores were playing in their ecosystems - as if bears suddenly became weasel-sized and weasels became bear-sized in their place", says Kammerer. The new species from Russia provide the first evidence that there was a worldwide turnover in predators after the mid-Permian extinction, and not just a localized turnover in South Africa.
Kammerer adds, "Kotelnich is one of the most important localities worldwide for finding therapsid fossils - not only because they are amazingly complete and well-preserved there, but also because they provide an all-too-rare window into mammal ancestry in the Northern Hemisphere during the Permian".
Copyright © ScienceDaily.
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Inverse / June 9, 2018
Russian Skeletons Show the Bubonic Plague Has Killed People for 4,000 Years
Scientists sequence the oldest genome linked to the disease.
Международная группа палеогенетиков (Германия, Россия, Швейцария, Китай) расшифровала геном старейшего из известных штаммов бактерии чумы Yersinia pestis, обнаруженного в захоронении возрастом 3800 лет на территории Самарской области. Оказалось, что в древности на территории Евразии существовали не одна, а две линии чумы, различавшиеся степенью вирулентности и механизмом передачи.
Hidden in the bones of ancient humans lies evidence of diseases that continue to distress people today. Recently, the examination of two 3,800-year old skeletons revealed the presence of a Yersinia pestis strain, famously the bacterium that causes plague. This strain is now the oldest of its kind sequenced to date, and suggests that the devastation that is the bubonic plague has a Bronze Age origin.
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The discovery, published Friday in Nature Communications, pushes back the proposed age of the bubonic plague by 1,000 years. It also adds to the understanding of a disease that is still reported between one and seven times per year in the United States, despite its more ancient reputation: In the U.S. 80 percent of plague cases have been in the bubonic form. Although it's been present throughout much of recorded history - it was the drive behind some of humanity's deadliest pandemics including the Justinian Plague and the Black Death - the origin and age of the disease have remained largely a mystery.
"Contrary to previous studies suggesting that Y. pestis was unable to cause disease during that time, we provide evidence that bubonic plague has been affecting humans for at least the last 4,000 years", study co-author Maria Spyrou tells Inverse.
Spyrou is an ancient DNA researcher at the Max Planck Institute for the Science of Human History. For her Ph.D., she's been focused on studying the evolutionary history of plague for the past four years: In this particular project, she and her team turned to human remains from the Bronze Age to hunt for it. Overall the researchers analyzed nine individuals from tombs at a site within the Samara region of Russia. Two of the individuals, buried within the same grave, were found to be infected with Y. pestis at the time of their death.
"We have recently come to realize that the Bronze Age was a period of massive population turnovers in Eurasia, and human movements during this time may have facilitated or have been facilitated by the spread of infectious disease", explains Spyrou. "The Eurasian Steppe, where our studied material comes from, seems to have been a key region to the human migrations and transformations which happened during that time".
Spyrou and her team reconstructed the Y. pestis genomes from these remains, an accomplishment which, they write, "suggests that the full ability for flea-mediated transmission causing bubonic plague evolved more than 1,000 years earlier than previously suggested". They propose that during the Bronze Age there were several Y. pestis lineages, some of which persist today. The genome sequenced here was likely an ancestral strain to later epidemics, like the Black Death.
Y. pestis strands of a similar age have been found before, but in those studies, the genomes didn't show the genetic signatures that are needed for the bubonic form of the disease. Specific characteristics are what makes this plague efficiently transmit from fleas, to rodents, to humans and other mammals. If the strain lacks genetic components that makes it possible for fleas to contract and pass it, then there's no bubonic plague.
Spyrou explains that Y. pestis diverged from a mild bacterium called Yersinia pseudotuberculosis which lives predominantly in the soil, then later acquired the ability to transmit through fleas of the gain of certain genes (like one that colonizes the flea's gut) and the loss of others (like another gene that makes the bacterium toxic to fleas).
It still exists today because of this ability to jump from creature to creature.
"Interestingly, plague is not a disease that is adapted to humans - it's not a human disease", says Spyrou. "Y. pestis is rather a bacterium that lives and replicates predominantly among wild rodents. The fact that it lives predominantly among rodents is one of the main reasons why it is so difficult to eradicate".
That it infects humans, Spyrou elaborates, is an unlucky situation mostly fueled by chance. Now it's obvious that humans have been unlucky in this matter for longer than ever realized.
Термин «научная дипломатия» появился менее десяти лет назад, хотя само явление существует уже давно. Международные научные контакты не прерываются при обострении политических отношений, сама же наука выступает в роли общего языка, помогая снизить политическую напряженность и объединяя государства для решения трансграничных проблем, которые невозможно решить силами одной страны.
It's no secret that United States-Russia relations are currently rife with tension and mistrust. The news is full of reports of Russia meddling in U.S. elections, seeding U.S. media with fake news, supporting the Syrian regime and so on.
The relationship between the two countries has reached an all-time low since the fall of the Soviet Union, with some going so far as to call it a new "cold war". Diplomats have been unable to mend the relationship, as national security interests on each side are too narrow to provide common ground.
But there are avenues of collaboration beyond the security realm that can help to balance strained relationships, maintain open channels of communication and build trust, enabling a more positive diplomatic process overall.
One key avenue is science. As a common and apolitical language, science brings allies and adversaries together with technology and innovation to address cross-border challenges that exist across the Earth - think climate, disease pandemics and international trade - which are out of reach for a single nation to address alone.
Since the 1950s, the U.S. and Russia have been cooperating continuously in a four specific international spaces - the high seas, Antarctica, outer space and deep sea - and the mechanism for cooperation has consistently been science. For instance, they cooperate on the 1959 Antarctic Treaty, which preserves the continent for peaceful purposes as the first nuclear arms agreement with scientific research as the basis for international cooperation. Similarly, in space, collaboration between the U.S. and the Soviet Union on the Apollo-Soyuz Test Project in 1975 led to the design of an international docking system, creating a physical bridge for subsequent operations and joint experiments that we see with the International Space Station today.
The term "science diplomacy" is recently coined, with the first book in this new field emerging from the 2009 Antarctic Treaty Summit. But this diplomatic approach has long existed in practice. As both an academic who studies science diplomacy and a practitioner who implements it, I suggest that science can help bridge contemporary political differences between the superpowers as well as other actors, promoting cooperation and preventing conflict across the world.
A different avenue for diplomacy
People usually think of diplomacy as how states represent themselves and negotiate to advance their own interests. These are the fraught high-level talks between nations that are featured on newspapers' front pages. Diplomats on each side angle and negotiate to come out on top of a particular issue with political expediency. Picture the sit-down in Singapore between President Trump and North Korea's Kim Jong Un.
Science diplomacy is different, operating across a continuum of urgencies from political to sustainability time scales. Nations are still coming together to discuss and resolve cross-border issues. But what's on the table revolves around common interests revealed across generations by science - including natural sciences and social sciences as well as indigenous knowledge - providing a foundation for negotiation that is far less politically charged and divisive to discuss and resolve the topics of the day.
For example, countries came together to share resources and design a joint response to two recent pandemics: Zika in Latin America and Ebola in West Africa. Following the easing of U.S.-Cuba relations in December 2014, scientists from the two countries began to collaborate on cancer research.
Science diplomacy also supports economic prosperity, balancing environmental protection and societal well-being through innovation. Countries are sharing and collaborating on technologies that will help transition resource-based economies to knowledge-based economies. This kind of cooperation can yield poverty-alleviating solutions along with progress across a suite of sustainable development goals.
Science diplomacy is also about contributing to informed decision-making by sharing evidence and options, without advocacy. This kind of exchange helps ensure the diplomatic process is objective and inclusive, relying on our leaders to make decisions that have legacy value. Imagine if a group of diplomats got together in a negotiating room to assess and design a response to a pandemic without consulting and involving medical and public health experts. It wouldn't make sense. The recent Iran nuclear deal, for instance, relied on scientists' expertise to build common interests among nations as the prelude for an agreement, providing an ongoing basis for cooperation despite political variability.
Collaboration between scientists from different countries can help create pathways for working together on controversial issues, more generally. For example, SESAME is the Middle East's first major international research center. It's designed to host both Israeli and Palestinian scientists. Instead of career diplomats and statesmen focused on pushing national agendas, researchers and practitioners with particular scientific expertise are focusing on research to address shared questions, divorced from politics. The CERN particle accelerators in Europe have demonstrated the value of this kind of scientific collaboration among nations since the 1950s.
And with cooperation and trust among scientists from diverse nations, there can be a ripple effect of goodwill between the nations involved, including agreements that would otherwise be difficult or impossible to negotiate at the time with any hope of continuity.
An Arctic environment example
My own involvement with U.S.-Russia relations started with chairing the first formal dialogue between NATO and Russia regarding environmental security in the Arctic Ocean. This 2010 dialogue at the University of Cambridge was funded by NATO along with other organizations and co-directed with the Moscow State Institute of International Relations. It involved four Russian ministries with representative to the president of Russia as well as experts and senior diplomats from 16 other nations.
As academics, my Russian colleagues and I were able to create an apolitical platform for a conversation that had never taken place. Matters related to military security had otherwise prevented open consideration of strategies to promote cooperation and prevent conflict around the North Pole, which remains a region of significant strategic interest with nuclear submarines. Here, science diplomacy brought together two long-estranged actors to productively address a security issue of common interest to both.
Since 2009, and despite ongoing diplomatic tensions, the U.S. and Russia have co-chaired three task forces under the auspices of the Arctic Council, the region's intergovernmental forum for sustainable development and environmental protection. And they've successfully led to three binding legal agreements among all eight Arctic states: Canada, Denmark, Finland, Iceland, Norway and Sweden, along with Russia and the U.S.
The most recent agreement just came into force in May 2018 to enhance international Arctic scientific cooperation. It reflects an understanding among these nations: International scientific collaboration is essential to pursue sustainable solutions, transcending national interests to maintain peace, stability and constructive cooperation in the Arctic. Science diplomacy offers a route that works both politically and practically.
International agreements, without politics
Science is a neutral platform that allows for less politically charged dialogues, which in turn create bridges that help overall diplomatic efforts.
Over the years, science diplomacy has helped build common ground and peacefully manage international spaces, as well as achieve technological breakthroughs that have global relevance, from health care to the digital revolution. There is every reason for science to continue helping to maintain important channels of communication in the face of current tensions and all yet to come.
For today's globally interconnected and growing civilization, which is confronting rapid transformation on the back of advances in science, technology and innovation, science diplomacy offers a unique process to build our common future.
Copyright © 2010-2018, The Conversation Trust (UK) Limited.
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Nature / 13 June 2018
World Cup ban on radioactive chemicals frustrates Russian biochemistry labs
The restrictions exacerbate what is already a difficult situation for Russian biochemists.
Проходящий в России Чемпионат мира по футболу привел к тому, что ряд российских биохимических лабораторий остался без необходимых реактивов - их продажа и перевозка запрещена из соображений безопасности. Это не считая обычных проблем с заказом материалов для исследований - бюрократии, долгих сроков внутренней поставки, отсутствия отечественных производителей, ограничений на импорт - которые ставят российских ученых в невыгодное положение по сравнению с исследователями в странах, где есть достаточный запас химического и научного оборудования.
Football fans around the world are eagerly awaiting the kickoff of the World Cup in Russia on 14 June. But some Russian researchers might find themselves with more time to watch the matches than they expected.
Because of security and counter-terror measures enacted by the government ahead of the World Cup tournament, some Russian labs will go without the radioactive reagents that they urgently need for their research, according to molecular biologists and biochemists who spoke to Nature.
In a presidential decree issued on 11 May, the Russian government suspended the sale and transport of hazardous chemical and biological substances, including toxic and radioactive chemicals, for two months, citing security concerns. The World Cup runs until 15 July. The decree applies only to cities hosting the matches, but many of these, including Moscow, happen to be research hubs, says Konstantin Severinov, a biochemist at the Skolkovo Institute of Science and Technology (Skoltech) near Moscow.
Labs out of luck
The measures threaten to stall the relatively little molecular-biology research that exists in Russia, says Severinov. Last month, Russian researchers who had recently ordered radioactive nucleotides, which they use to measure gene expression and for other assays, got bad news from the Russian Academy of Science's Institute of Bioorganic Chemistry in Moscow: an expected June delivery to their labs would be cancelled because of the presidential decree. No other Russian centre supplies such reagents.
"This jeopardizes the whole workflow in my lab", says Severinov, who is also group leader at the Russian Academy of Science's Institutes of Molecular Genetics and Gene Biology in Moscow. Numerous projects - including CRISPR-Cas9 gene-editing experiments and those measuring the effects of toxins on cells - have been affected, he says.
Stephen O'Brien, director of the Theodosius Dobzhansky Center for Genome Bioinformatics in St. Petersburg, says his team's work, which is largely computational, hasn't been affected. But he has heard from colleagues at other institutes who are having trouble getting radioactive reagents and other toxic chemicals.
Maintaining lab supplies of research reagents and other consumables is notoriously problematic in Russia, O'Brien adds. Russian production capacities are scarce, and severe customs restrictions effectively bar scientists who depend on radio-labelled reagents from legally purchasing them from foreign suppliers, Severinov says.
Meanwhile, domestic supply is routinely hampered by bureaucracy and long delivery times. "We always have problems with ordering research materials during summer", says Ilya Osterman, a biochemist at the Skoltech Center for Translational Biomedicine in Moscow, who uses the chemicals to examine the shapes of different RNA molecules and to measure gene expression. "The World Cup only makes the situation worse".
To prevent delays and frustrating disruptions to their research, scientists in Russia must order such reagents several weeks in advance, through their institution's procurement department. With the World Cup and the ensuing summer break, the next deliveries of radio-labelled nucleotides might not arrive until early autumn. "This means a bad disruption", says Severinov.
"Four of my PhD students are caught midway in their thesis work".
Alexei Khokhlov, a vice-president of the Russian Academy of Sciences, which runs the institute that supplies researchers with radio-labelled nucleotides, did not reply to an e-mail from Nature asking how many scientists were affected and how the delay might affect their research.
Before his re-election as president in March, Vladimir Putin promised to strengthen Russia's struggling research base. But high customs and import restrictions on research materials continue to put Russian scientists at a competitive disadvantage compared with researchers in countries where there is an ample supply of chemicals and science equipment, says Fyodor Kondrashov, a Russian biologist at the Institute of Science and Technology Austria in Klosterneuburg.
The enhanced security restrictions will be lifted soon after the World Cup final is played at the Luzhniki Stadium in Moscow on 15 July. "This current crisis might be short-lived", says Kondrashov. "But it underlines the difficulty of doing cutting-edge research in a country that is not entirely free".
© 2018 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.
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На основе результатов совместных исследований морских экосистем Баренцева моря, проводимых Норвежским институтом морских исследований и Полярным научно-исследовательским институтом морского рыбного хозяйства и океанографии (Мурманск), Международный совет по исследованию моря рекомендовал значительно снизить вылов некоторых видов рыб, а добычу морского окуня прекратить вовсе.
The International Council for the Exploration of the Sea (ICES) recommends the 2019 quota for cod to be set to a maximum of 674,678 tons for the Barents Sea. That is down 100,000 tons compared with the 2018 quotas.
The Council's advice is based on joint studies of the current stock by scientists from Norway's Institute of Marine Research (IMR) and the Marine Institute (PINDRO) in Murmansk, Russia. Each year, the scientists sail criss-cross the entire Barents Sea counting cod juveniles and different ages of cod. Also, the amount of capelin and herring, which the cod eat, is important when estimating the future sustainability of the cod stock.
Researcher Harald Gjøsæter is Norway's member to ICES's advisory committee. He says also quotas for other fish spices need to be reduced for 2019. "Haddock is recommended to be reduced from 202,305 tons to 152,000 tons and the Pollock quota should be reduced from 172,500 tons to 149,550 tons", Gjøsæter says. Rose fish should not be fished at all so quota advice is set to zero.
Norwegian and Russian marine researchers have formally cooperated for 60 years in the Barents Sea, collecting information about the marine ecosystem, and made joint recommendations for how much fish should be end up as dinner for humans.
Authorities, however, do not necessarily comply with the advises from the scientists, although the final quotas are normally more or less in line with the guidelines for how much fishing the different spices can stand to be sustainable.
In October, the Norwegian-Russian fishery commission meet to agree on the final quotas for next year. The Barents Sea is considered to be one of the best-managed oceans worldwide in regards to the sustainability of fishing and ecosystem understanding.
Last year, scientists recommended the quota for Northeast Arctic cod to be 712,000 tons while the final quota was agreed to be 775,000 tons. Peak-year was 2013, when the cod quota was set to 1 million tons.
© The Independent Barents Observer AS © 2015-2018.
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У млекопитающих (за исключением водных) и птиц, как и у людей, сон делится на фазы, медленную и быструю. Российские и американские биологи обнаружили, что у морских котиков (Callorhinus ursinus) две фазы сна на суше. Засыпая же в воде, животные обходятся быстрой фазой и спят каждым полушарием по очереди, что помогает избежать переохлаждения мозга.
Lorsqu'il est dans l'eau, cet animal repose ses hémisphères l'un après l'autre et ne connaît pas de phase de sommeil paradoxal.
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Tous les mammifères et les oiseaux dorment de la même façon que nous: il y a alternance de phases de sommeil léger, lent et paradoxal. Ce dernier est caractérisé par des mouvements oculaires rapides (REM). C'est le moment où l'on rêve. Depuis la découverte de ce sommeil paradoxal par le Dr Michel Jouvet dans les années 1950, son utilité reste bien mystérieuse. Et voici que l'otarie à fourrure du Nord (Callorhinus ursinus) apporte une réponse. Ou du moins un début de réponse.
Des chercheurs russes et américains ont étudié le sommeil de ces mammifères aquatiques du nord du Pacifique. Et ont découvert un fait surprenant: quand cet ours de mer dort sur terre, il fait comme tous les autres, alternance classique des différentes phases. Mais lorsqu'il dort en mer - c'est là qu'il passe la majorité de son temps -, il n'y a aucun sommeil paradoxal. Et ce pendant des jours.
Garder le cerveau au chaud
C'est que l'otarie ne dort que d'un hémisphère cérébral à la fois, tout comme le fait le dauphin. Il dort légèrement sur le côté en plaçant ses nageoires d'une certaine façon. Sa tête est placée de telle façon qu'il a un œil sous l'eau, ouvert, dirigé vers le bas, le deuxième étant fermé, dirigé vers le ciel. La menace pour lui ne vient pas du ciel, il ne craint pas les oiseaux, mais bien du bas d'où ses prédateurs, orques ou requins, peuvent surgir. Tandis que l'hémisphère cérébral qui dirige l'œil sous l'eau (hémisphère droit pour l'œil gauche et inversement) reste en activité, celui qui commande l'œil émergé est «éteint».
Pour Oleg Lyamin, du delphinarium de Moscou, qui travaille avec Jerome Siegel à l'université de Californie à Los Angeles, l'hémisphère qui fonctionne suffit à garder le cerveau au chaud. Pas besoin de sommeil à mouvements oculaires rapides pour le «chauffer» de temps à autres. Lorsque l'animal revient à terre et retrouve un sommeil «classique», il n'y a d'ailleurs pas de «rattrapage» de sommeil paradoxal, preuve que son utilité est relative.
Une phase de sommeil paradoxal dure une vingtaine de minutes (et 25 % de la nuit). Le cerveau profiterait aussi de cette phase de chauffe pour effectuer du rangement. Il est en effet communément admis que le sommeil lent est la phase de récupération et de réparation du corps, tandis que le sommeil paradoxal serait celui du «rangement» du cerveau, en particulier sur les processus de mémorisation.
Благодаря опытам по электромагнитной манипуляции заряженными частицами в условиях невесомости, проводившимся на МКС несколько лет, была разработана новая технология 3D-печати биологических тканей. Космический эксперимент показал, что живые клетки можно собирать в трехмерные структуры с помощью магнитного поля.
Thanks to the research of magnetic levitation in the conditions of microgravity, a new technology for 3D printing of biological tissues was developed. In the future, this technology will help to create radiation-sensitive biological constructs and repair damaged tissues and human organs. The results are published in Biofabrication. The technology is based on the results of the experimental studies which were supported by Russian Science Foundation (RSF).
There are many methods of 3D-bioprinting. Most of them use a certain layer-by-layer framework of the biological tissues. The resulting bulk material is then sent to the incubator where the cultivation continues. There are ways in which biological objects are developed without the use of multi-layer approach, for example, magnetic bioprinting, when the cell material is directed to the desired location by means of the magnetic fields. In this case, the cells should be labeled in some way with magnetic nanoparticles.
The researchers from the 3D BioprintingSolutions company in collaboration with the other Russian and foreign scientists developed the new method of bioprinting that allows to create 3D-biological objects without the use of layer-by-layer approach and magnetic labels. This new method was developed with the contribution from the Joint Institute for High Temperatures of the Russian Academy of Sciences (JIHT RAS).
"During the period from 2010 to 2017, a series of unique experimental studies were carried out aboard the Russian Orbital Segment of the International Space Station at the experimental setup "Coulomb Crystal".
The main element of that device is an electromagnet that creates a special inhomogeneous magnetic field in which the structures of the diamagnetic particles (they are magnetized against the direction of the magnetic field) can be formed in the microgravity conditions", as explained by one of the authors, Mikhail Vasiliev, head of laboratory of dusty plasma diagnostics in JIHT RAS.
In their experimental study, the JIHT researchers described how small charged particles behave in the magnetic field of a special shape under the microgravity conditions, including zero gravity. In addition, the scientists developed a mathematical model of this process based on the methods of molecular dynamics. These results explain how to obtain homogeneous and extended three-dimensional structures consisting of the thousands of the particles.
The conventional methods of magnetic 3D-bioprinting had a number of limitations associated with the gravity. To reduce the influence of the gravitational forces, one can increase the power of magnets that control the magnetic field. However, this will complicate the bioprinter considerably.
The second way is to reduce the gravity. A group of scientists from 3D BioprintingSolutions used this approach. The new method is called "formative three-dimensional biofactory" and it allows you to create three-dimensional biological structures not in layers but immediately from all the sides. The researchers applied the experimental data and the results of the mathematical modeling obtained by the JIHT RAS scientists to control the shape of such structures.
"The results of the Coulomb crystal experiment on the study of the formation of the spatially ordered structures led to the development of a new method for the formative 3D-biofactory of the tissue-like structures based on the programmable self-assembly of the living tissues and organs under the conditions of gravity and microgravity by means of an inhomogeneous magnetic field", summarized the author.
Bioprinters based on the new technology application will be able to create various biological constucts that can be used, for example, to estimate the adverse effects of the space radiation on the health of the astronauts in the long-term space missions. In addition to that, according to the authors, this technology will be able to restore the function of the damaged tissues and organs in the future.
Copyright 1995-2018 - Space Media Network.
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Археологи Тюменского государственного университета, отслеживая путь казацкого отряда Ермака в 1581-1585 гг., проверили летописные сведения о его зимовке на реке Тобол. Раскопанная на Карачинском острове стоянка была в итоге датирована серединой XVII века, а значит, принадлежала другим сибирским первопроходцам. С другой стороны, это указывает на высокую скорость похода - дорога до столицы Сибирского ханства без зимовки заняла два месяца.
Following the trail of Siberian pioneers, archaeologists from the University of Tyumen have investigated the camp on Karachinsky Island, the Lower Tobol River, and confirmed the high speed of the Cossacks' campaign, reports RIA news agency.
Yermak Timofeyevich, a Cossack ataman who started the conquest of Siberia, is known to every citizen of Russia. Confirmed by a number of chronicles, the importance of his campaign is undeniable. However, as there is not enough detailed information in literary sources, scientists are actively pursuing archaeological research in this direction.
The expedition excavated a dugout on Karachinsky Island where, according to chronicles, Yermak and his Cossacks spent a winter. Judging by the remains of logs, the dugout had two rooms and a cellar. However, it can be concluded that the building only existed for a short period of time as the area around it was not developed and there was little household waste and garbage. Burn marks on some of the logs suggest that the dugout survived a fire, after which it was renovated and used again.
The AMS Laboratory at the University of Arizona (USA) analysed wood samples and dated the building to the middle of the 17th century, while Yermak's campaign took place in the years 1581-1585. Soil analysis revealed that the island had once been used for cattle raising and handicraft production.
"Taking into consideration the results of the analysis, we believe that Yermak did not spend the winter there", said Professor Natalia Matveeva, the expedition leader.
It is possible that other Siberian explorers could have set up camps on Karachinsky Island. According to one of the versions, the Cossacks marched from the Stroganov towns to the capital of the Siberian Khanate without wintering. "This decision was tactically effective as the Tatar troops, weakened by their participation in Khan Mametkul's raid on the Urals, showed little resistance", suggested Matveeva.
Copyright © 2018 by the American Association for the Advancement of Science (AAAS).
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Археологи Института истории материальной культуры РАН нашли в зоне подтопления Саяно-Шушенской ГЭС каменный саркофаг с мумифицированными останками женщины, жившей около 2 тысяч лет назад. Находка стала возможной благодаря сильному понижению уровня воды в водохранилище, открывшему затопленную с 1980-х гг. территорию.
A team of researchers from St Petersburg's Institute of History of Material Culture has found the naturalized remains of a mummy in an ancient gravesite near the Sayano-Shushenskaya Dam in Russia. In speaking with the press, the researchers reported that the remains were those of a mummified young girl lying in a stone gravesite and that they believe she lived almost 2000 years ago.
The archaeologists reported that along with the remains, there was a belt with beads and a buckle made of jet, a vase resembling those used by Huns of the period, and a box made of birch wood that held a small mirror. Other assorted ceramic utensils were also found. Initial examination of the mummified remains revealed patches of skin, soft tissue and cloth remnants that appeared to be made of silk.
The researchers noted that the area where the grave was found is normally underwater, but this year, the reservoir created by the dam was abnormally low, exposing ground that had been submerged since the 1980s. As the researchers were exploring the exposed land last month, they came upon the tomb.
The researchers suggest the clothing and materials in the grave indicate the girl was likely a nomadic Hun - likely one of high regard. She could have been part of the nobility. They also note that the vase contained what appeared to be a funeral meal and that a sack of pine nuts had been placed on her chest. The Huns, the researchers note, lived in parts of what is now modern China and Siberia almost 2000 years ago. They were migratory, and prior studies have shown they tended to mix with local people.
The remains and other artifacts have been removed from the gravesite and have been transported to a location suitable for studying them. The researchers report that a lot of work is required to learn more about the girl's origins and how she came to be mummified. They will also be working to understand how her remains and other artifacts were able to withstand being submerged under the reservoir for over 30 years.
© © Phys.org 2003-2018, Science X network.
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Phys.Org / June 28, 2018
"Leaders", "successors", and "toilers": Mathematicians classify physicists and other scientists
Ученые Московского физико-технического института и Института проблем управления им. В.А.Трапезникова РАН классифицировали математиков, физиков и психологов, разделив их на три типа в зависимости от стиля работы, восприятия их научным сообществом и эффекта от публикаций. Работа опубликована на портале Math-Net.Ru.
As of 2013, there were 7.8 million researchers globally, according to UNESCO. This means that 0.1 percent of the people in the world professionally do science. Their work is largely financed by governments, yet public officials are not themselves researchers. To help governments make sense of the scientific community, mathematicians from the Moscow Institute of Physics and Technology and Trapeznikov Institute of Control Sciences have devised a researcher typology. Their paper, in Russian, was published in the journal Large-Scale Systems Control. It is available for download from MathNet.Ru, a Russian math research repository.
Researchers in various fields, from psychology to economics, build models of human behavior and reasoning to categorize people. But it does not happen as often that scientists undertake an analysis to classify their own kind.
However, research evaluation, and therefore scientist stratification as well, remain highly relevant. Six years ago, the government outlined the objective that Russian scientists should have 50 percent more publications in Web of Science- and Scopus-indexed journals. As of 2011, papers by researchers from Russia accounted for 1.66 percent of publications globally. By 2015, this number was supposed to reach 2.44%. It did grow but this has also sparked a discussion in the scientific community about the criteria used for evaluating research work.
The most common way of gauging the impact of a researcher is in terms of his or her publications. Namely, whether they are in a prestigious journal and how many times they have been cited. As with any good idea, however, one runs the risk of overdoing it. In 2005, U.S. physicist Jorge Hirsch proposed his h-index, which takes into account the number of publications by a given researcher and the number of times they have been cited. Now, scientists are increasingly doubting the adequacy of using bibliometric data as the sole independent criterion for evaluating research work. One obvious example of a flaw of this metric is that a paper can be frequently cited to point out a mistake in it.
Scientists are increasingly under pressure to publish more often. Research that might have reasonably been published in one paper is being split up into stages for separate publication. This calls for new approaches to the evaluation of work done by research groups and individual authors. Similarly, attempts to systematize the existing methods in scientometrics and stratify scientists are becoming more relevant, too. This is arguably even more important for Russia, where the research reform has been stretching for years.
One of the challenges in scientometrics is identifying the prominent types of researchers in different fields. A typology of scientists has been proposed by Moscow Institute of Physics and Technology Professor Pavel Chebotarev, who also heads the Laboratory of Mathematical Methods for Multiagent Systems Analysis at the Institute of Control Sciences of the Russian Academy of Sciences, and Ilya Vasilyev, a master's student at MIPT.
In their paper, the two authors determined distinct types of scientists based on an indirect analysis of the style of research work, how papers are received by colleagues, and what impact they make. A further question addressed by the authors is to what degree researcher typology is affected by the scientific discipline.
"Each science has its own style of work. Publication strategies and citation practices vary, and leaders are distinguished in different ways", says Chebotarev. "Even within a given discipline, things may be very different. This means that it is, unfortunately, not possible to have a universal system that would apply to anyone from a biologist to a philologist".
"All of the reasonable systems that already exist are adjusted to particular disciplines", he goes on. "They take into account the criteria used by the researchers themselves to judge who is who in their field. For example, scientists at the Institute for Nuclear Research of the Russian Academy of Sciences are divided into five groups based on what research they do, and they see a direct comparison of members of different groups as inadequate".
The study was based on the citation data from the Google Scholar bibliographic database. To identify researcher types, the authors analyzed citation statistics for a large number of scientists, isolating and interpreting clusters of similar researchers.
Chebotarev and Vasilyev looked at the citation statistics for four groups of researchers returned by a Google Scholar search using the tags "Mathematics", "Physics", and "Psychology". The first 515 and 556 search hits were considered in the case of physicists and psychologists, respectively. The authors studied two sets of mathematicians: the top 500 hits and hit Nos. 199-742. The four sets thus included frequently cited scientists from three disciplines indicating their general field of research in their profiles. Citation dynamics over each scientist's career were examined using a range of indexes.
The authors initially identified three clusters, which they tentatively labeled as "leaders", "successors", and "toilers". The leaders are experienced scientists widely recognized in their fields for research that has secured an annual citation count increase for them. The successors are young scientists who have more citations than toilers. The latter earn their high citation metrics owing to yearslong work, but they lack the illustrious scientific achievements.
Among the top 500 researchers indicating mathematics as their field of interest, 52 percent accounted for toilers, with successors and leaders making up 25.8 and 22.2 percent, respectively.
For physicists, the distribution was slightly different, with 48.5 percent of the set classified as toilers, 31.7 percent as successors, and 19.8 percent as leaders. That is, there were more successful young scientists, at the expense of leaders and toilers. This may be seen as a confirmation of the solitary nature of mathematical research, as compared with physics.
Finally, in the case of psychologists, toilers made up 47.7 percent of the set, with successors and leaders accounting for 18.3 and 34 percent. Comparing the distributions for the three disciplines investigated in the study, the authors conclude that there are more young achievers among those doing mathematical research.
A closer look enabled the authors to determine a more fine-grained cluster structure, which turned out to be remarkably similar for mathematicians and physicists. In particular, they identified a cluster of the youngest and most successful researchers, dubbed "precocious", making up 4 percent of the mathematicians and 4.3 percent of the physicists in the set, along with the "youth" - successful researchers whose debuts were somewhat less dramatic: 29 and 31.7 percent of scientists doing math and physics research, respectively. Two further clusters were interpreted as recognized scientific authorities, or "luminaries", and experienced researchers who have not seen an appreciable growth in the number of citations recently. Luminaries and the so-called inertia accounted for 52 and 15 percent of mathematicians and 50 and 14 percent of physicists, respectively.
There is an alternative way of clustering physicists, which recognizes a segment of researchers, who "caught the wave". The authors suggest this might happen after joining major international research groups.
Among psychologists, 18.3 percent have been classified as precocious, though not as young as the physicists and mathematicians in the corresponding group. The most experienced and respected psychology researchers account for 22.5 percent, but there is no subdivision into luminaries and inertia, because those actively cited generally continue to be. Relatively young psychologists make up 59.2 percent of the set. The borders between clusters are relatively blurred in the case of psychology, which might be a feature of the humanities, according to the authors.
"Our pilot study showed even more similarity than we'd expected in how mathematicians and physicists are clustered", says Chebotarev. "Whereas with psychology, things are noticeably different, yet the breakdown is slightly closer to math than physics. Perhaps, there is a certain connection between psychology and math after all, as some people say".
"The next stage of this research features more disciplines. Hopefully, we will be ready to present the new results soon", he concludes.
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