The latest drone and satellite technology is helping an international team of researchers to better understand how the vast, treeless regions called the tundra is becoming greener.

As Arctic summer temperatures warm, plants are responding. Snow is melting earlier and plants are coming into leaf sooner in spring. Tundra vegetation is spreading into new areas and where plants were already growing, they are now growing taller.

Understanding how data captured from the air compare with observations made on the ground will help to build the clearest picture yet of how the northern regions of Europe, Asia and North America are changing as the temperature rises.

Now a team of 40 scientists from 36 institutions, led by two National Geographic Explorers, have revealed that the causes of this greening process are more complex — and variable — than was previously thought.

Researchers from Europe and North America are finding that the Arctic greening observed from space is caused by more than just the responses of tundra plants to warming on the ground. Satellites are also capturing other changes including differences in the timing of snowmelt and the wetness of landscapes.

Lead author Dr Isla Myers-Smith, of the University of Edinburgh’s School of GeoSciences, said: “New technologies including sensors on drones, planes and satellites, are enabling scientists to track emerging patterns of greening found within satellite pixels that cover the size of football fields.”

Professor Scott Goetz of the School of Informatics, Computing and Cyber Systems at Northern Arizona University, says this research is vital for our understanding of global climate change. Tundra plants act as a barrier between the warming atmosphere and huge stocks of carbon stored in frozen ground.

Changes in vegetation alter the balance between the amount of carbon captured and its release into the atmosphere. Small variations could significantly impact efforts to keep warming below 1.5 degrees centigrade — a key target of the Paris Agreement. The study will help scientists to figure out which factors will speed up or slow down warming.

Co-lead author Dr Jeffrey Kerby, who was a Neukom Fellow at Dartmouth College while conducting the research, said: “Besides collecting new imagery, advances in how we process and analyse these data — even imagery that is decades old — are revolutionising how we understand the past, present, and future of the Arctic.”

Alex Moen, Vice President of Explorer Programs at the National Geographic Society, said: “We look forward to the impact that this work will have on our collective understanding of the Arctic for generations to come.”

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“Neutrinos continue to intrigue us and stretch our imagination. These ‘ghost particles’ are the least understood in the standard model, but they hold the key to what lies beyond,” said Bhupal Dev, assistant professor of physics in Arts & Sciences and author of a new study in Physical Review Letters.

“So far, all nonstandard interaction studies at IceCube have focused only on the low-energy atmospheric neutrino data,” said Dev, who is part of Washington University’s McDonnell Center for the Space Sciences. “The ‘Zee burst’ mechanism provides a new tool to probe nonstandard interactions using the ultra-high energy neutrinos at IceCube.”

Ultra-high energy events

Since the discovery of neutrino oscillations two decades ago, which earned the 2015 Nobel Prize in physics, scientists have made significant progress in understanding neutrino properties — but a lot of questions remain unanswered.

For example, the fact that neutrinos have such a tiny mass already requires scientists to consider theories beyond the standard model. In such theories, “neutrinos could have new nonstandard interactions with matter as they propagate through it, which will crucially affect their future precision measurements,” Dev said.

In 2012, the IceCube collaboration reported the first observation of ultra-high energy neutrinos from extraterrestrial sources, which opened a new window to study neutrino properties at the highest possible energies. Since that discovery, IceCube has reported about 100 such ultra-high energy neutrino events.

“We immediately realized that this could give us a new way to look for exotic particles, like supersymmetric partners and heavy decaying dark matter,” Dev said. For the previous several years, he had been looking for ways to find signals of new physics at different energy scales and had co-authored half a dozen papers studying the possibilities.

“The common strategy I followed in all these works was to look for anomalous features in the observed event spectrum, which could then be interpreted as a possible sign of new physics,” he said.

The most spectacular feature would be a resonance: what physicists witness as a dramatic enhancement of events in a narrow energy window. Dev devoted his time to thinking about new scenarios that could give rise to such a resonance feature. That’s where the idea for the current work came from.

In the standard model, ultra-high energy neutrinos can produce a W-boson at resonance. This process, known as the Glashow resonance, has already been seen at IceCube, according to preliminary results presented at the Neutrino 2018 conference.

“We propose that similar resonance features can be induced due to new light, charged particles, which provides a new way to probe nonstandard neutrino interactions,” Dev said.

Bursting onto the neutrino scene

Dev and his co-author Kaladi Babu at Oklahoma State University considered the Zee model, a popular model of radiative neutrino mass generation, as a prototype for their study. This model allows for charged scalars to be as light as 100 times the proton mass.

“These light, charged Zee-scalars could give rise to a Glashow-like resonance feature in the ultra-high energy neutrino event spectrum at the IceCube Neutrino Observatory,” Dev said.

Because the new resonance involves charged scalars in the Zee model, they decided to call it the ‘Zee burst.’

Yicong Sui at Washington University and Sudip Jana at Oklahoma State, both graduate students in physics and co-authors of this study, did extensive event simulations and data analysis showing that it is possible to detect such a new resonance using IceCube data.

“We need an effective exposure time of at least four times the current exposure to be sensitive enough to detect the new resonance — so that would be about 30 years with the current IceCube design, but only three years of IceCube-Gen 2,” Dev said, referring to the proposed next-generation extension of IceCube with 10 km3 detector volume.

“This is an effective way to look for the new charged scalars at IceCube, complementary to direct searches for these particles at the Large Hadron Collider.”

Decade-long structural studies by Fang Li of the University of Minnesota, et al. have shown how the SARS virus (SARS-CoV) interacts with animal and human hosts in order to infect them. The mechanics of infection by the Wuhan coronavirus appear to be similar. These investigators used the knowledge they gleaned from multiple SARS-CoV strains — isolated from different hosts in different years — and angiotensin-converting enzyme-2 (ACE2) receptors from different animal species to model predictions for the novel Wuhan coronavirus. (Both viruses use ACE2 to gain entry into the cell, but it serves normally as a regulator for heart function.)

“Our structural analyses confidently predict that the Wuhan coronavirus uses ACE2 as its host receptor,” the investigators wrote. That and several other structural details of the new virus are consistent with the ability of the Wuhan coronavirus to infect humans and with some capability to transmit among humans.

“Alarmingly, our data predict that a single mutation [at a specific spot in the genome] could significantly enhance [the Wuhan coronavirus’s] ability to bind with human ACE2,” the investigators write. For this reason, Wuhan coronavirus evolution in patients should be closely monitored for the emergence of novel mutations at the 501 position in its genome, and to a lesser extent, the 494 position, in order to predict the possibility of a more serious outbreak than has been seen so far.

The research is published in the Journal of Virology, a journal of the American Society for Microbiology. The study provides the basic, translational and public health research communities with predictive insights that may help study and battle this novel coronavirus.

For more information on the new strain of coronavirus, visit ASM’s Novel Coronavirus (2019-nCoV) Resources page: https://www.asm.org/Press-Releases/2020/nCoV2019-Resources

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Senior author Professor Gabriel Leung from the University of Hong Kong highlights: “Not everyone who is infected with 2019-nCoV would require or seek medical attention. During the urgent demands of a rapidly expanding epidemic of a completely new virus, especially when system capacity is getting overwhelmed, some of those infected may be undercounted in the official register.”

He explains: “The apparent discrepancy between our modelled estimates of 2019-nCoV infections and the actual number of confirmed cases in Wuhan could also be due to several other factors. These include that there is a time lag between infection and symptom onset, delays in infected persons coming to medical attention, and time taken to confirm cases by laboratory testing, which could all affect overall recording and reporting.”

The new estimates also suggest that multiple major Chinese cities might have already imported dozens of cases of 2019-nCoV infection from Wuhan, in numbers sufficient to initiate local epidemics.

The early estimates underscore that it will likely take rapid and immediate scale-up of substantial public health control measures to prevent large epidemics in areas outside Wuhan. Further analyses suggest that if transmissibility of 2019-nCoV could be reduced, both the growth rate and size of local epidemics in all cities across China could be reduced.

“If the transmissibility of 2019-nCoV is similar nationally and over time, it is possible that epidemics could be already growing in multiple major Chinese cities, with a time lag of one to two weeks behind the Wuhan outbreak,” says lead author Professor Joseph Wu from the University of Hong Kong. “Large cities overseas with close transport links to China could potentially also become outbreak epicentres because of substantial spread of pre-symptomatic cases unless substantial public health interventions at both the population and personal levels are implemented immediately.”

According to Professor Gabriel Leung: “Based on our estimates, we would strongly urge authorities worldwide that preparedness plans and mitigation interventions should be readied for quick deployment, including securing supplies of test reagents, drugs, personal protective equipment, hospital supplies, and above all human resources, especially in cities with close ties with Wuhan and other major Chinese cities.”

In the study, researchers used mathematical modelling to estimate the size of the epidemic based on officially reported 2019-nCoV case data and domestic and international travel (i.e., train, air, road) data. They assumed that the serial interval estimate (the time it takes for infected individuals to infect other people) for 2019-nCoV was the same as for severe acute respiratory syndrome (SARS: table 1). The researchers also modelled potential future spread of 2019-nCoV in China and internationally, accounting for the potential impact of various public health interventions that were implemented in January 2020 including use of face masks and increased personal hygiene, and the quarantine measures introduced in Wuhan on January 23.

The researchers estimate that in the early stages of the Wuhan outbreak (from December 1, 2019 to January 25, 2020) each person infected with 2019-nCoV could have infected up to 2-3 other individuals on average, and that the epidemic doubled in size every 6.4 days. During this period, up to 75,815 individuals could have been infected in Wuhan.

Additionally, estimates suggest that cases of 2019-nCoV infection may have spread from Wuhan to multiple other major Chinese cities as of January 25, including Guangzhou (111 cases), Beijing (113), Shanghai (98), and Shenzhen (80; figure 3). Together these cities account for over half of all outbound international air travel from China.

While the estimates suggest that the quarantine in Wuhan may not have the intended effect of completely halting the epidemic, further analyses suggest that if transmissibility of 2019-nCoV could be reduced by 25% in all cities nationally with expanded control efforts, both the growth rate and size of local epidemics could be substantially reduced. Moreover, a 50% reduction in transmissibility could shift the current 2019-nCoV epidemic from one that is expanding rapidly, to one that is slowly growing (figure 4).

“It might be possible to reduce local transmissibility and contain local epidemics if substantial, even draconian, measures that limit population mobility in all affected areas are immediately considered. Precisely what and how much should be done is highly contextually specific and there is no one-size-fits-all set of prescriptive interventions that would be appropriate across all settings,” says co-author Dr Kathy Leung from the University of Hong Kong. “On top of that, strategies to drastically reduce within-population contact by cancelling mass gatherings, school closures, and introducing work-from-home arrangements could contain the spread of infection so that the first imported cases, or even early local transmission, does not result in large epidemics outside Wuhan.”

The authors point to several limitations of their study, including that the accuracy of their estimates depend on their assumption about the zoonotic source of infection in Wuhan. They also highlight that the models assume travel behaviour was not affected by disease status and that all infections eventually have symptoms — so it is possible that milder cases have gone undetected which could underestimate the size of the outbreak. Lastly, they note that their epidemic forecast was based on inter-city mobility data from 2019, and might not reflect mobility patterns in 2020, particularly in light of the health threat posed by 2019-nCoV.

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In December 2019, an outbreak of apparently viral pneumonia of unknown etiology emerged in the city of Wuhan, in the Chinese province of Hubei.

On January 9, 2020, the Chinese health authorities and the World Health Organization (WHO) announced the discovery of a novel coronavirus, known as 2019-nCoV, which was confirmed as the agent responsible for the pneumonia cases.

Over the weekend of January 11-12, the Chinese authorities shared the full sequence of the coronavirus genome, as detected in samples taken from the first patients. “Sequencing the genome of pathogens is crucial for the development of specific diagnostic tests and the identification of potential treatment options,” explains Sylvie van der Werf, Director of the National Reference Center (CNR) for Respiratory Viruses at the Institut Pasteur.

Friday January 24, 2020. Detection of the virus confirmed in France

On Friday January 24, late in the morning, the Institut Pasteur received samples of three suspected cases (two patients in Paris and one in Bordeaux). “Using the samples taken from these patients, we detected the novel coronavirus,” says Sylvie Behillil, Deputy Director of the CNR at the Institut Pasteur.

From Friday January 24, 2020. Viral genome sequenced at the Institut Pasteur

That same Friday evening, scientists launched the process of sequencing the viral genome based on the samples. The CNR prepared the material for sequencing, ready for P2M to begin work immediately the following Monday. The sequencing run was completed by early evening on the Tuesday, and the scientists used data analysis to obtain the sequence of the whole genome in two of the first three confirmed cases in France. “This proves the efficacy of the CNR’s process of analysis based on viral sequencing,” continues Vincent Enouf.

Thursday January 30, 2020. The Institut Pasteur obtains and shares the whole sequence of the virus

The P2M platform (see below) currently performs at an extremely high level; the average time taken to produce sequences ranges from three days (for emergencies) to a maximum of ten days. In this case, it took just three days for the whole sequence to be determined: “We performed data analysis during the night from Tuesday to Wednesday, then corroborated the results on Wednesday with counter analysis,” explains Vincent Enouf. “The whole sequence was confirmed in just three days.”

What can we learn from it? “The sequences were identical in all our samples. One member of the couple must have contaminated the other, as the virus is the same.” The two full sequences of the virus isolated in two of the first French cases were submitted to the Global Initiative on Sharing All Influenza Data (GISAID) platform, which was initially developed to share sequences and monitor the genetic evolution of influenza viruses, a process that is vital to determine the composition of the influenza vaccine. A special “coronavirus” tab has been created so that the scientific community can work together and advance at a quicker pace.

“Around twenty other sequences of the novel coronavirus genome have been obtained worldwide, and if we compare them with ours, we can see that they are all very close; there is not much diversity in the viruses analyzed, which suggests that coronavirus 2019-nCoV did not need to mutate in order to adapt and spread,” continues Vincent Enouf.

The National Reference Center (CNR) for Respiratory Viruses at the Institut Pasteur in Paris is one of WHO’s reference laboratories for coronavirus 2019-nCoV.

A total of eight people from the CNR and two from the P2M sequencing platform have been working on the virus this week and will continue to monitor the outbreak in France.

P2M, a state-of-the-art mutualized platform for microbiology also open to external CNRs

P2M is also available to external CNRs for sequencing. In 2019 it worked with four CNRs based outside the Institut Pasteur. The platform sequences bacteria, viruses, parasites and fungi. Thanks to experience gained over the past five years (since 2015), P2M today offers a highly efficient service, as shown by a first-pass success rate (i.e. a high-quality sequence providing comprehensive information on the entire genome) of more than 95% in 2019. Sequence production takes between three days (for emergencies) and ten days at most.

In 2019, P2M sequenced around 25,000 pathogens. Genome sequencing increases the sensitivity threshold for outbreak detection. Early identification of outbreaks by the Institut Pasteur’s scientists (clustered cases in a short space of time caused by the same pathogen) enables epidemiologists to get to work immediately to determine the origins of the outbreak, and the authorities to coordinate the public health response.

Lithium-ion technology still dominates energy-storage applications, but it has intrinsic disadvantages, among which are the price, environmental issues, and the flammability of the electrolyte. Therefore, in next-generation technologies, scientists are replacing the lithium ion with more abundant and much cheaper ions, such as the potassium ion. However, potassium and potassium-ion batteries also face safety issues, and nonflammable electrolytes are not yet available for them.

Materials scientist Zaiping Guo, and her team from the University of Wollongong, Australia have found a solution. The researchers developed an electrolyte based on a flame-retardant material and adapted it for use in potassium batteries. Besides providing nonflammability, it could be operated in batteries at concentrations that are suitable for large-scale applications, write the scientists.

This novel electrolyte contained triethyl phosphate as the sole component of the solvent. This substance is known as a flame retardant. It has been tested in lithium-ion batteries, but only very high concentrations provided enough stability for long-term operation, too high for industrial applications. The battery industry demands dilute electrolytes, which are cheaper and ensure better performances. By using potassium ions, however, the concentrations could be reduced, the authors reported. They combined the phosphate solvent with a commonly available potassium salt and obtained an electrolyte that did not burn and allowed stable cycling of the assembled battery concentrations of 0.9 to 2 moles per liter, which are concentrations that are suitable for larger scales; for example, in smart-grid applications.

Key to that performance was the formation of a uniform and stable solid-electrolyte interphase layer, according to the authors. They observed this layer, which ensures operability of the electrodes, only with the phosphate electrolyte. Conventional carbonate-based electrolytes were unable to build up this layer. The authors also reported high cycling stability; whereas, under the same conditions, the conventional carbonate-based electrolyte decomposed.

Guo and her team have demonstrated that next-generation potassium-ion batteries can be made safe by using a novel inorganic, phosphate-based electrolyte. They suggest that electrolytes based on flame retardants can be developed further and could be used for the design of other nonflammable battery systems.

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Using the style of a ‘personal diary’, Rafelski firstly reviews and summarises decades of work. Describing leading experimental and theoretical contributions, he recounts how and why strange quarks are produced so efficiently in QGP, and how this behaviour has been exploited for QGP discovery. He also explores strangeness as a tool in the search and discovery of this primordial phase of matter; existent at unimaginably high temperatures and pressures. He then follows the line of research through to the ongoing experimental ultra-high-energy experiments involving head-on collisions between both heavy nuclei and lighter protons, carried out at CERN’s Large Hadron Collider (LHC).

Secondly, Rafelski follows the narrative with a commented set of his own unpublished work, focusing on pioneering theories and QGP discovery. He also includes a selection from the comments of referees offering both criticism and praise for these studies; along with his own present-day perspectives. This review highlights the numerous successes enjoyed by theorists, through decades of tireless effort to explain and understand the primordial QGP. All the same, it shows that many pressing questions remain to be answered. Rafelski continues to contribute to the field through his rich research experience and will undoubtedly inspire new generations of physicists to continue the study of exotic quarks in the primordial Universe.

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Journal Reference:

1. Johann Rafelski. Discovery of Quark-Gluon Plasma: Strangeness Diaries. The European Physical Journal Special Topics, 2020; 229 (1): 1 DOI: 10.1140/epjst/e2019-900263-x