Physicists working on LIGO–Virgo have confirmed the detection of 39 gravitational-wave signals by the observatories in April–October 2019. This brings the total catalogue of confirmed observations of gravitational waves to 50.
While these 39 signals have been public knowledge for some time – indeed we have covered several of them in Physics World – this announcement from LIGO–Virgo comes as the detections are described in papers that have been submitted for peer review.
According to the LIGO and Virgo collaborations, the upturn in the number of detections was achieved by making significant improvements to the gravitational-wave detectors – which are kilometre-scale interferometers in the US and Italy. Upgrades included boosting the laser power, better mirrors and the use of quantum squeezing technology.
With the expanded catalogue, researchers could study the remnant objects produced by the mergers. They were able to rule out the creation of “echoes” after the main merger signals, which suggests that remnants behave as predicted by Einstein’s general theory of relativity.
The 39 signals were detected in the first half of run three of the observatories and scientists are still analysing data from the second half. Meanwhile, LIGO and Virgo are undergoing further upgrades and will be joined in their fourth observing run by the KAGRA detector in Japan.
The mystery of where heavy elements such as gold and silver come from has deepened with research groups clashing over whether binary neutron-star mergers can account for the abundance of those elements in the universe.
On 17 August 2017 a burst of gravitational waves was detected by the LIGO and Virgo detectors. Astronomers quickly turned their telescopes towards the source of the waves and observed the afterglow of a kilonova – the collision of two neutron stars – in a galaxy 140 million light-years away.
The light of the kilonova was powered by the radioactive decay of large amounts of heavy elements formed by rapid neutron capture (the “r-process”). In particular, a team led by Darach Watson at the Niels Bohr Institute at the University of Copenhagen identified the spectral line of strontium in the kilonova’s light.
Enough collisions
It is now certain that neutron-star collisions produce r-process elements such as strontium, europium, silver and gold. However, debate continues as to whether there are enough such collisions to produce the abundance of those elements that we observe in the universe.
In a paper submitted to Monthly Notices of the Royal Astronomical Society, astronomers led by Irina Dvorkin of the Institut d’Astrophysique de Paris studied how the interstellar medium becomes enriched in r-process elements and concluded that binary neutron-star mergers are the main source of these elements in environments that have generally low levels of heavy elements. These regions include the Milky Way’s halo, dwarf galaxies and the early universe. Although their models did not focus on environments richer in heavy elements, such as the Milky Way’s disc, they propose that binary neutron-star mergers could also be the dominant source there too.
One of their reasons for this conclusion is the observed variations in the ratios of r-process element abundances compared to iron-group elements, which are formed in supernovae. If r-process elements were also formed in supernovae, we would expect them to have a constant ratios relative to the iron-group elements. Instead, there is a large scatter observed in the ratios of the two element groups, implying different origins.
Timescale too long
However, this conclusion is disputed by a paper in The Astrophysical Journal by Chiaki Kobayashi of the University of Hertfordshire and team. Kobayashi and colleagues created models describing the origin of every element in the universe as a function of time and environment. They came to the conclusion that the timescale of binary neutron stars forming from supernovae and then spiralling into a collision is too long to explain the observed abundance of r-process elements.
“The important difference between our paper and the Dvorkin et al. paper is the time delay of neutron-star merger events,” Kobayashi tells Physics World. Following their formation, binary neutron stars could take billions of years to get close enough to collide. However, some binary neutron stars may be able to merge much faster; for example, PSR J0737-3039 – the only double pulsar discovered so far – is a relatively young binary neutron-star system that will merge within a timescale of 85 million years.
Dvorkin adds, “In my opinion, the fraction of fast mergers needs to be further studied, as it’s clearly central to the question of the early production of heavy elements.”
If a significant number of binary neutron stars can undergo fast mergers, it will speed up the rate at which they enrich the interstellar medium – the gas and dust between stars – with r-process elements.
Watson, who made the key strontium discovery in the kilonova afterglow, acknowledges that observations are currently contradictory. “The amount of material produced in small dwarf galaxies [with low heavy-element abundances] is, I believe, largely inconsistent with neutron star production,” he says. “However, I also believe that it may be possible for neutron stars to merge on fast timescales.”
Sub-micron diamonds
Watson points out another line of evidence not considered in the Dvorkin or Kobayashi papers: nanodiamonds. These are tiny, sub-micron diamonds that can form in a variety of environments in space, from star-forming regions to asteroid collisions, but some nanodiamonds also contain r-process elements. Since neutron-star collisions do not produce nanodiamonds, the only other possible source of r-process enriched nanodiamonds is supernovae, says Watson.
Although the scatter in the ratios of r-process elements to iron-group elements observed by Dvorkin’s team seems to rule out ordinary supernovae, Kobayashi proposes a new type of exploding star called a magneto-rotational supernova. However, there is no direct evidence for the existence of such supernovae and the debate regarding the origin of r-process elements will continue to rumble on.
Low-electron temperatures are a key requirement to explore exotic quantum states such as Majorana fermions and Fibonacci particles, with potential applications towards topological qubits and next-generation quantum processors.
This webinar introduces the Proteox5mK system from Oxford Instruments, an ultra-low base temperature system designed to allow researchers to achieve their lowest electron temperatures for improved resolution in quantum transport measurements, such as the fractional quantum hall effect.
Further benefits are discussed, with the high cooling power and low vibration applicable to a wider range of applications.
Following this, Dr Levitin talks about the benefits of low temperature for research including electrons in 2D electron gas and semiconductor nanodevices, fragile ordered states in heavy-fermion metals, and bulk topological superconductors.
During the Q&A we also welcome Dr Harriet van der Vliet, the quantum engineer at Oxford Instruments NanoScience to join the team.
James Robinson graduated with a materials science degree from the University of Oxford. He gained a background in plasma technology prior to joining Oxford Instruments Nanoscience as a product manager for the company’s ultra-low temperature systems. Responsible for the new Proteox® system, James has developed a vast knowledge of its usability and unique features that makes it an ideal alternative tool for the low-temperature research.
The thermodynamically instable nature of lithium metal in liquid electrolytes significantly delays the implementation of the high-energy rechargeable lithium battery technology in electrical vehicles. Although many approaches have been proposed to rescue Li metal anodes, most of the work is performed in small-scale coin cells and tested in the conditions drastically different from the reality. A full knowledge of Li metal activities at the cell level is lacking but extremely critical for the success of developing next-generation rechargeable Li metal batteries.
This webinar will start with discussing the root causes of forming Li metal dendrite in liquid batteries from an electrochemistry point of view and then step into understanding the implications of Li metal dendrites in realistic high-energy pouch cells. The recent progress of Battery500 Consortium will be discussed to highlight the importance of applying electrochemistry principles to understand, identify and address the fundamental challenges in realistic battery technologies.
Dr Jie Xiao is currently a laboratory fellow and group leader of the Battery Materials and System Group at the Pacific Northwest National Laboratory. She holds a joint position at the Department of Chemistry and Biochemistry at the University of Arkansas. Xiao is an ECS fellow and serves as the ECS Battery Division secretary. She received her PhD in materials chemistry from the State University of New York at Binghamton. Xiao has been leading research on practical applications and the fundamental study of energy-storage materials and systems, spanning from microbatteries for acoustic fish tags to advanced battery technologies for vehicle electrification and grid-energy storage. She has published more than 100 peer-reviewed journal papers, two book chapters, and holds 17 US patents in the energy-storage research area. Xiao has been a top 1% Clarivate Analytics Highly Cited Researcher since 2017.
Assume nothing K Renee Horton’s invisible disability of hearing loss and her visible identity as a Black woman in science interact in complex ways. (Courtesy: Steven Seipel)
When I walk into a room, most people see me as confident and ready to take on the world. As an engineer in the aerospace industry, that’s the persona I would like them to see. But in reality, I’m most likely experiencing a serious level of anxiety stimulated by my invisible disability.
The Invisible Disabilities Association defines an invisible disability as a physical, mental or neurological condition that can’t be seen from the outside yet can limit or challenge a person’s movements, senses or activities. Mine is hearing loss. Most people I know forget that I deal with this disability daily. My speech is not altered, and my hearing aids are small enough for most people to miss them. But within academia, once I disclose my disability, there is an almost immediate assumption that I have some type of intellectual deficiency.
Hearing is the ability to perceive sound by detecting vibrations through your ears. Sound waves enter the outer ear and travel to your eardrum, which through some detailed process creates an electrical signal that the auditory nerve carries to the brain. There the signal becomes something that we recognize and understand. A hearing impairment or hearing loss is a full or partial decrease in the ability to detect or understand sounds. My hearing loss is in the range of frequencies used for speech. I have extreme difficulty with heavily accented speakers from other parts of the US or different countries, as well as in excessively noisy environments, like conferences. I’m always on high alert when moving in these environments, making sure my brain has processed what I heard and trying to hold up my end of an intellectual conversation.
Hearing is exhausting when you suffer from a hearing loss. I’m constantly focused on making sure that my frustration doesn’t show when I don’t hear clearly or am missing gaps of conversation because my brain hasn’t processed what was said. I dread having to ask colleagues to repeat themselves because they always rephrase their statement as if I didn’t understand its meaning, versus just not hearing the words.
Even if you don’t have a disability, many of you can identify with me in different ways. When I walk into a room, I’m Black. When I walk into a room, I’m a woman. When I walk into a room, I’m a Black woman. Different people process these things differently. Historically, Black people have been perceived as less intelligent, and even though physics is considered an elite intellectual pursuit, there are some who believe that Black physicists are in the field or in their jobs only because of affirmative action or because of luck. The current political environment has allowed racism to rear its ugly head, amplifying the negative experiences for African Americans, even in our field. Add to that my disability, and some have questioned whether I have the intellectual capacity to be in physics.
Barriers to full participation
In graduate school I had a professor whom I had a lot of trouble understanding. I was unable to process any of what he was saying, even with all my accommodations in place. I earned a C in this class, which led to my being placed on academic probation. I had to retake the class with the same professor. Knowing I needed a new approach, I went to the professor to try and work something out. His response was “You are the dumbest student I’ve ever taught.” I’ve never forgotten these words. They are what pushed me to work my butt off from that day forward. In this situation, my race and gender didn’t matter – my disability was the only hindering factor. The meeting with my professor was a pivotal moment in my academic career because it forced me to take ownership of my disability and not let it lead me.
Several years ago I attended an International Union of Pure and Applied Physics conference as a member of the organizing committee for the Women in Physics Working Group. I applied for a grant to accommodate my disability at the conference. However, one of my colleagues – a grant administrator and a white American woman – decided she knew what was best and overrode my accommodation requests with her own choices. Her decision caused several days of frustration, several tears and several days of not being able to fully participate in the conference.
Eventually the conference made the accommodations I needed, and I was able to fully participate and fulfil my functional responsibilities. It cost the conference organizers twice as much as the amount in my grant request. I processed this experience as a microaggression, which the Oxford English Dictionary defines as “an instance of indirect, subtle, or unintentional discrimination against members of a marginalized group such as a racial or ethnic minority”. My colleague needed to be in control of the entire situation, and she decided I either didn’t know what was best for me or wasn’t worth the cost of the accommodation I needed. She perceived me as aggressive and angry because I wanted the accommodation corrected, as is my civil right under the Americans with Disabilities Act of 1990.
Intersecting identities
I’ve pointed out my hidden disability. Know that there are so many more people who similarly suffer from other types of invisible disabilities. Sometimes the hardest thing to navigate is knowing if people have issues with me because I’m Black, because I’m a woman, because I’m a Black woman, because I’m a person with a disability, because they perceive that I have an edge due to my accommodations, or because of a combination of all my intersecting identities – none of which I could change even if I wanted to.
Just a small reminder to anyone who doubts me: I belong here. I may keep crying in my personal space at the anxiety associated with my disability, but I won’t be going away.
A new and robust technique for generating microbubbles in films of graphene oxide has been developed by researchers in Australia, Singapore and the US. Using ultrashort laser pulses, researchers led by Han Lin at Swinburne University of Technology created stable bubbles with highly controllable volumes, curvatures, and positions. They then used the structures to make a near-perfect microlenses for producing photonic jets from white light. With further research, their technique could see a broad range of uses in other areas.
From inkjet printing to DNA manipulation, microbubbles have found uses in a diverse array of practical applications. Currently, they are generated by firing ultrasound waves or laser pulses onto solid substrates like silicon chips. For the process to work, however, these substrates must be immersed in liquids – resulting in unstable bubbles that form in random places. This makes them unsuitable for integration with many biological and photonics applications – which require highly stable bubbles with controllable volumes and curvatures.
Lin’s team gained better control over the process by placing a film of graphene oxide onto a substrate, which it irradiated with highly focused femtosecond laser pulses. This triggers a chemical reaction that releases gases, which become trapped by the impermeable film. Through careful control of the laser power and its exposure area, the researchers could finely tune the amount of gas released. This gives them precise control over the volumes and curvatures of the resulting microbubbles as well as the locations of the bubbles. Furthermore, the microbubbles can easily be eliminated by increasing the laser power and destroying the film.
Intense photonic jet
To showcase the applicability of their graphene oxide microbubbles, Lin and colleagues exploited their highly uniform surfaces and almost perfectly spherical curvatures to create microlenses. These can focus a range of optical wavelengths, without any unwanted dispersion. They demonstrated this capability by using a microlens to focus white light with a broad range of wavelengths into an intense photonic jet, which they concentrated onto a single focal point with no chromatic aberration.
The team says that the technique offers clear advantages over photonic jet generation with glass microspheres. Compared with this more traditional approach, the extremely high tunability of the graphene oxide microbubbles means that micolenses have arbitrary focal lengths and an insensitivity to material dispersion. These attributes are highly desirable in applications including 3D biological imaging in miniaturized lab-on-a-chip devices. Ultimately, the team’s discoveries open up promising new routes towards the application of microbubbles in a broad range of situations, including imaging, spectroscopy, and sensing.
Micro- and mini-beam radiation therapies (MBRTs) have been shown in animal experiments to effectively destroy tumours while minimizing damage to normal tissue nearby. MBRT is delivered by irradiating a tumour with a series of high-dose beamlets of protons or photons alternated with low-dose valleys. The reduced side-effects to organs-at-risk are thought to be due to the differential response of normal and tumour tissue to such spatially fractionated radiation. The mechanisms underlying this differential response, however, are still unknown.
Aiming to fill this gap in knowledge, researchers in Germany have proposed and investigated a chemical mechanism to describe the efficacy of mini-beams and micro-beams. They performed a simulation study to find a surrogate to the tumour control seen in MBRT. Building on a proposed correlation between tissue damage and the level of reactive oxygen species (ROS) in tissue, the team examined whether the distribution of a radiation-induced molecule or radical could provide such a surrogate.
“From all published animal studies with micro- and mini-beams, it was clear that dose coverage of the tumour in the valley region was too low to allow any form of tumour control. So the dose delivered to the tumour was not a good surrogate for establishing the biological effect,” explains senior author Joao Seco from DKFZ. “Several years ago, my group started working in radiochemistry, with the focus of evaluating which radical or molecule could be a good surrogate of biological effect.”
In a study described in Frontiers in Physics, Seco and colleagues investigated 12 potential generic radicals and molecules (gRMs) produced by a radiation beam. As physical dose coverage is not achieved in MBRT, they hypothesized that biological damage is instead provided by the distribution of such a gRM reaching a uniform coverage of the tumour target.
As such, they proposed that a candidate gRM must meet four conditions: it should be stable enough to diffuse during beam-on to cover the dose-valley regions; it should reach a steady state in production versus removal, within a few microseconds; it should be a product of water radiolysis; and it should have oxidizing capacity to create cellular damage.
The researchers, also from Heidelberg University and GSI, used the Monte Carlo code TRAX-CHEM to model the production, removal and diffusion of the 12 gRMs. The simulations revealed that the steady state was only reached by three of the gRMs, with only one of these – hydrogen peroxide (H2O2) – an oxidizing species. Thus they restricted all further analysis to H2O2.
Two-dimensional representation of the temporal diffusion of molecules and radicals produced by a proton beam, simulated with TRAX-CHEM. (Courtesy: CC BY 4.0/Front. Phys. 10.3389/fphy.2020.564836)
To assess the potential of H2O2 as a candidate for the biological efficacy of MBRT, the researchers evaluated their simulations against previous animal experiments. One limitation of TRAX-CHEM is that it only runs up to 10-6 s. So to extend their predictions to times suitable for experimental comparison (up to 103 s), they modelled the time evolution of H2O2 with a convolution model that uses a Gaussian Kernel (calculated from TRAX-CHEM) to convert delivered dose into H2O2 spatial distribution at a specified time.
They calculated the H2O2 spatial distribution for four proton mini-beam and photon micro-beam studies, using the published values of peak spacing, peak FWHM and peak-to-valley dose ratio (PVDR). Based on these parameters, they calculated the beam-on time at which the H2O2 distribution reached a uniform tumour coverage.
Comparisons with the actual irradiation times revealed that the calculated minimum irradiation times were reached in three of the four experiments. In these cases, the predicted H2O2 distribution had a coverage of at least 95%. The team notes that these three experiments were all associated with high probabilities of tumour ablation or growth delay.
Prediction of the minimum beam-on time required to achieve uniform H2O2 coverage for two synchrotron experiments. (Courtesy: CC BY 4.0/Front. Phys. 10.3389/fphy.2020.564836)
In the experiment that did not reach the minimum beam-on time, the model predicted that H2O2 did not uniformly cover the target. In this experiment (which used synchrotron-generated X-ray microbeams), only two tumours were ablated in 32 irradiated rats. In contrast, an experiment using the same synchrotron beams but with smaller spacing, in which H2O2 diffused uniformly over the target, produced five tumour ablations out of 11 rats.
The researchers surmise therefore that homogeneous H2O2 distribution is a highly relevant parameter for tumour ablation and should be further investigated. The fact that this uniform coverage may be generated in the tumour but not in normal tissue, combined with the higher tolerance of normal cells to ROS relative to cancer cells, may underlie the differential effect between tumour and normal tissue in MBRT.
Seco notes that the developed model can be used to assess whether MBRT will provide uniform H2O2 coverage of the tumour volume. There is still a need, however, to investigate the correlation between this coverage and treatment response. The team is looking to discuss with other groups a possible animal study to understand how H2O2 could be used to quantify treatment response.
“In our study, we demonstrated that we should use H2O2 – not dose – as a marker of biological effect for micro- and mini-beam radiotherapy,” Seco concludes.
Battle ground Republican Donald Trump or Democrat Joe Biden (pictured) will have to deal with the fallout from the COVID-19 pandemic. (Courtesy: Michael Stokes/CC BY 2.0)
Next week’s presidential election between the incumbent Republican Donald Trump and his Democratic rival Joe Biden presents voters with a stark choice between two candidates with strikingly different views of national and international policy. With issues such as how to halt the spread of COVID-19 and how to resuscitate an economy battered by the pandemic, science has played a key role in an election that sees a strongly divided electorate head to the polls on 3 November.
In a report released in March just as the pandemic was starting to bite, the American Institute of Physics (AIP) noted that the pandemic-related shutdown had already “stalled research, curtailed the operation of major facilities and international travel, and negatively impacted students and early career scientists”. AIP chief executive Michael Moloney noted in June that without swift action to rebuild and renew, the US was in “peril of losing the resilient and robust physical sciences enterprise we need to remain healthy, innovative and prosperous”.
Opponents of Trump have accused his administration of being “anti-science” – a concern that has increased during the pandemic. Critics highlight his failure to accept medical authorities’ recommendations for lessening the impact of COVID-19 and his insistence on promoting unproven remedies. They also point to Trump’s dismissal of anthropogenic climate change as a hoax – following recent devastating wildfires in California he claimed that “it’ll start getting cooler” – and his administration’s consistent efforts to cut funding for science in its annual budget proposals.
So far, however, Congress has refused to agree to those reductions. “Had they gone along with the requested cuts, funding for science would be down by 50%,” says Neal Lane, a physicist and former presidential science adviser who is now a senior fellow in science and technology policy at Rice University. “I’ve seen no signs from Trump’s side that he has much interest in science.”
The difference in this election is the number of cases in which the two parties differ on the merits of science itself – as if science is on the ballot, in a way
Criticism of the Trump administration’s science policy started in its earliest days when it pulled the US out of the Paris climate agreement. Environmentalists were further incensed by the relaxation of environmental protection regulations created under Democratic president Barack Obama. Another problem is the current administration’s perceived suspicion of “experts”, exemplified by a failed effort to ban academic scientists from the Environmental Protection Agency’s scientific advisory panels. The Washington Postreported earlier this year that 20% of high-level science positions in the civil service are currently vacant.
International policy during Trump’s tenure has also caused some angst in the US science community. “The US has always been a leader in international collaboration,” says Philip Bucksbaum, chair of natural science at Stanford University and current president of the American Physical Society (APS). “But that’s begun to change because of disagreements with China.”
Bucksbaum points to several high-profile arrests of scientists accused of risking US national security, while in September the Department of Homeland Security revoked the US visas of more than 1000 Chinese students and researchers, citing security risks. “That sends a chilling message,” says Busksbaum, who emphasizes that his comments represent his personal views and not those of the APS. Such moves also have a potential impact on US universities given that international students make up about half of graduate students in the US – and a third of them come from China.
“Science affects everything the government does,” adds Bucksbaum. “The difference in this election is the number of cases at the national level in which the two parties differ on the merits of science itself – it feels as if science is on the ballot, in a way.”
A “shameful” moment
In early September 81 US science Nobel laureates, including 26 from physics, issued an open letter endorsing Biden – who was vice-president under Barack Obama from 2009 to 2017. “At no time in our nation’s history has there been a greater need for our leaders to appreciate the value of science in formulating public policy,” the laureates argued. “During his long record of public service, Joe Biden has consistently demonstrated his willingness to listen to experts, his understanding of the value of international collaboration in research, and his respect for the contribution that immigrants make to the intellectual life of our country.”
The letter was organized by Democratic Representative Bill Foster of Illinois, the only physicist currently in Congress, who said it would be an “important” development for the Biden campaign. Foster says that “a core group” of laureates decided which issues to raise in the letter, but when he started calling the laureates to back the initiative, “it was like pushing at an open door…there was a lot of enthusiasm because of the difference [the laureates] perceive in the scientific understanding” between the two candidates.
The Nobel laureates’ Democratic leanings are nothing new: similar letters were penned in 2016 to support Hillary Clinton and in 2008 for Barack Obama. More unusual, however, was a strongly worded editorial in Science in September by its editor-in-chief, the chemist Holden Thorp. Entitled “Trump lied about science”, Thorp claimed that the president’s remarks in February to Washington Post journalist Bob Woodward, in which he sought to downplay the severity of COVID-19, meant that “a US president ha[d] deliberately lied about science in a way that was imminently dangerous to human health and directly led to widespread deaths of Americans”. Thorp suggested this was “the most shameful moment in the history of US science policy”.
Meanwhile, political appointees of the Trump administration without medical backgrounds have been accused of meddling with health statistics and announcements of potential treatments for COVID-19. In late August, Food and Drug Administration director Stephen Hahn apologised for the administration’s release of statistics that greatly overstated the benefit of blood plasma in treating COVID-19.
Lunar vision
Republican supporters of Trump respond that his administration’s policies have improved the economy – at least until the coronavirus arrived. They point to recent initiatives that created centres for artificial intelligence and quantum information science. They also note a renewed effort to send astronauts to the Moon, as a starting point for a manned mission to Mars in the 2030s, and the debut – on the administration’s watch – of the commercial SpaceX system for ferrying astronauts to the International Space Station, which marked the end of US dependence on Russia’s Soyuz spacecraft.
Trump also has his defenders in the scientific community, particularly among deniers of climate change. Will Happer, an emeritus professor of physics at Princeton University who believes that carbon dioxide benefits living things, has served as an official and unofficial adviser to the president on climate change. Howard Hayden, an emeritus physicist at the University of Connecticut associated with the Heartland Institute, which promotes “free market solutions to social and economic problems”, says that Trump “has never been opposed” to science. “I don’t think Joe Biden has any particular credentials in the science community,” he adds. “I suspect the [Nobel laureates’ open] letter is more animated by animus for Trump than anything for science.”
This may be an opportunity for the scientific community to remind everyone about long-term investment in science
Neal Lane
Yet Trump’s own party has issued no science manifesto for the next four years. The administration’s annual memorandum on its R&D priorities, released in mid-August, will likely shape its future budget requests should Trump win re-election. The priorities include “industries of the future” such as artificial intelligence, quantum-information science, advanced communication networks and advanced manufacturing. The memorandum also foresees the creation of “Industries of the Future Institutes” that would house up to “a few thousand” researchers carrying out interdisciplinary R&D.
The Biden campaign’s manifesto, meanwhile, calls for $300bn on R&D over the next four years and $400bn over a decade to make “the largest-ever investment in clean energy research”. The plan targets a zero-emissions US by 2050 via R&D, investments in infrastructure, regulations on emissions and retraining of workers in traditional energy industries. The $300bn would serve “to sharpen Americans’ competitive edge in new industries [such as] battery technology, artificial intelligence, biotechnology and clean energy”.
Whoever wins the next election will have to spend extra on science, Lane believes. “Funding has been trending downward for the last decade or so,” he says. “What you need in science and R&D generally is sustainable, steady growth of government funding.” Foster agrees, adding that he sees the coronavirus pandemic as a factor in refocusing voters on the importance of science. “The only reason we’re in a position to develop vaccines rapidly is decades of scientific research,” he says. “This may be an opportunity for the scientific community to remind everyone about long-term investment in science.”
While the coronavirus pandemic wreaks havoc across national healthcare systems and the global economy, many technology companies have bunkered down and spent a good chunk of 2020 focusing on what they do best: relentless product innovation. A case study in this regard is the development team behind RadCalc QA secondary check software, a suite of widely deployed quality-assurance (QA) tools that provides medical physicists and dosimetrists with fully automated and independent dosimetric verification of their radiotherapy treatment planning systems (TPS).
Among a raft of advanced RadCalc features unveiled this year, top billing goes to the addition of automated 3D dose-volume verification – a result of the successful integration of Monte Carlo and collapsed-cone dose calculation algorithms into the platform. That 3D capability is reinforced by a continuous-improvement mindset – aligned with the evolving operational priorities of end-users at more than 2500 clinics worldwide – which ensures that automation, speed and workflow efficiency remain hard-wired into the RadCalc develop-and-release programme.
3D thinking
“For the past 20 years, we have provided independent QA software that’s fast, easy-to-use and accurate when it comes to identifying TPS dose errors,” explains Jim Dube, president and co-founder of the RadCalc software portfolio, part of LAP’s growing QA product line in radiotherapy. As such, the addition of automated 3D dose verification represents a natural progression for RadCalc, ensuring enhanced QA accuracy for harder-to-treat cases – for example, metastatic brain tumours or small tumour targets surrounded by lung heterogeneities – as well as an independent check for a range of advanced treatment modalities, including intensity-modulated radiation therapy (IMRT), volumetric modulated-arc therapy (VMAT), stereotactic radiosurgery (SRS), stereotactic body radiotherapy (SBRT) plus hypofractionation and ultrahypofractionation.
Jim Dube: “Independent verification is, and will remain, a big deal for medical physicists and for the radiotherapy equipment vendors.”
Under the hood, RadCalc’s 3D Monte Carlo module exploits the well-established BEAMnrc dose engine in tandem with proprietary machine modelling acquired from the medical physics team at McGill University, Canada. The collapsed-cone convolution superposition algorithm is the result of a separate acquisition covering the source code and related patents of a product called DosimetryCheck (purchased from US radiological software specialist Math Resolutions back in 2017). “Our investment in Monte Carlo and collapsed-cone algorithms gives users a higher degree of certainty in their QA 3D dose calculations,” adds Dube. “That certainty translates into improved targeting accuracy and dose distribution accuracy – and ultimately better patient outcomes.”
If accuracy is a given for 3D dose verification, so too are automation and speed. Put simply, says Dube, all the physicist has to do is export a treatment plan via their DICOM RT and RadCalc will automatically verify the plan using either a Monte Carlo or collapsed-cone algorithm, generating results in minutes. “If the treatment plan doesn’t pass versus preset criteria,” he adds, “RadCalc will prompt the user to investigate what’s going on using a suite of dose analysis tools. They can slice-and-dice the plan just about any way they want to see where the hot or cold spot is and figure out what to do from there.”
Buy vs subscribe
Functionality aside, there’s also significant innovation to report on the RadCalc commercial model – most notably the availability of subscription licensing for radiation oncology clinics in North America. In terms of specifics, end-users can now select from four preconfigured packages – Essential, 3D Premium, 3D Gold and 3D Unlimited – and add functional modules to meet their changing clinical needs. “We are constantly working on new features, new releases and the optimization of the software platform,” says Dube. “With a subscription, users can access all the latest features to ensure they are always up to date.”
Annual and multiyear RadCalc subscription packages are available, all with technical support and maintenance included. The financial driver here is that even in the best of times – let alone the middle of a pandemic – the upfront capital outlay on a traditional QA software licence can prove a blocker for smaller clinics, many of which struggle to accommodate spending spikes outside their annual budgeting cycle.
The RadCalc subscription model offers customers a fast-track workaround, spreading their software investment over an extended timeframe. “Subscription packages provide 70% lower upfront spend compared to traditional licence fees,” claims Dube. “It’s a win–win, with the client getting much-improved visibility and certainty about their QA software spending over time.”
Listening to the user
Right now, the RadCalc team is hard at work fleshing out the development roadmap for 2021 and beyond, including the release of 3D EPID-based functionality to underpin true measurement-based IMRT QA and in vivo verification. In short, RadCalc will import the necessary EPID data/image files, process them, and then send to the collapsed-cone dose engine to calculate the dose.
Ongoing requirements-gathering and prioritization are built upon what Dube calls “dialogue at scale” with the clinical user base – though he concedes that “it’s suddenly not so easy to gather ideas from customers in a face-to-face setting” as the main scientific conferences and tradeshows go virtual.
All things considered, though, it seems the collective conversation on RadCalc is in good shape, with the technical support and sales teams very much the “eyes and ears” for customer feedback and new feature requests. “Our annual customer survey is another fantastic channel to inform our product development,” says Dube, “and very much in the spirit of ‘what are we doing well, what could we do better, what can we do to make your life easier?’”
Operationally, RadCalc’s incorporation into the LAP group (in January 2019) has also opened up new growth opportunities through the latter’s global customer base. LAP laser systems are used worldwide for patient positioning in radiotherapy, both in the imaging and treatment unit. More broadly, the company is focused on delivering the enabling technologies for next-generation radiation therapy with ongoing innovation across its QA and multileaf-collimator product lines.
Capitalizing on that access, Dube concludes, starts and ends with RadCalc’s core value proposition to the radiation oncology community: “Independent verification is, and will remain, a big deal for medical physicists and for the radiotherapy equipment vendors. Why wouldn’t they want independent QA providing a double-check of their treatment plans?”
The search for extraterrestrial intelligence (SETI) is slowly evolving from a fringe endeavor to a more mainstream one thanks to improvements in the capability of astronomical surveys, detector sensitivity, and greater philanthropic financial support. Still, because of the vastness of the universe and the scarcity of resources, scientists must develop strategies around where, when, and how to discover alien civilizations.
Much of SETI involves trying to receive signals broadcast by other civilizations. However, it could be that every civilization in the universe has decided that transmitting messages for other civilizations to receive is unwise or dangerous, but that listening for messages sent by others is a safe and worthwhile pursuit.
This “SETI Paradox” would leave all SETI efforts doomed to failure because for any civilization’s SETI efforts to succeed, some other civilization must engage in messaging extraterrestrial intelligence (METI). One important question is how two civilizations should coordinate their efforts to discover each other, given that they are not certain about each other’s existence. Another is which civilization should send a message, and which should listen.
Onus to transmit
In a recent preprint, astronomer Eamonn Kerins of the UK’s University of Manchester has developed a game-theory framework that determines not only how and where civilizations should target their efforts, but also which of two such civilizations has the onus to send a message, and which should be listening for that message.
As Jason Wright, professor of astronomy and astrophysics at Penn State, summarizes, “Kerins’ idea is that the symmetry that keeps us all from transmitting can be broken by recognizing that some species have access to more information about other planets, and that the ‘onus to transmit’ should lie with them”. He adds, “It’s a neat approach and suggests that there are systems towards which we have the onus to transmit and should be contacting, while other [planets] are better targets for listening. If other species are following the same logic, then this should make SETI programs more efficient and likely to succeed.”
Kerins considers the scenario in which both civilizations can gather data that suggests the existence of the other. Ideally, each civilization should gather similar data because only when the data are comparable would the civilizations possess “mutual” information – which is key to Kerins’ framework. Because the civilizations may vastly differ in their technological capabilities, it is important that they both consider the simplest possible evidence of the other’s existence.
“Common denominator information”
Kerins proposes that civilizations should use “common denominator information” (CDI) to find potential SETI/METI targets. CDI is evidence that both parties can recognize, and that is independent of either party’s particular method of acquiring information. Kerins offers the example of the amount of starlight blocked by a planet as it transits across its host star – which is called the transit’s signal strength.
This quantity is simple enough that any civilization engaged in SETI/METI efforts should be capable of measuring it, and it is also independent of how the measurement is made. In this sense, a transit’s signal strength is “intrinsic” and therefore can be compared by two civilizations who are looking for one another. Crucially, each party should be able to determine not only their own signal strength as the other party would measure it, but also the signal strength of the other planet. Then, each party would know what the other knows, and therefore both parties know who has the superior evidence about the other’s potential existence.
Kerins argues that whichever party has superior information has the greater incentive to send a message to the other – the onus to transmit – while the party with inferior information should listen for a signal.
On where and how to implement his game-theory framework, Kerins points to planets in the “Earth’s transit zone” (ETZ), a slice of space in which an observer can watch Earth transit the Sun. “From the basic idea of transits, and with technology comparable to ours, [extraterrestrial civilizations in the ETZ] can work out that we are a potentially habitable planet,” says Kerins. “The transit method is among the first methods that any civilization capable of finding other planets would establish. Therefore, if there are SETI-capable civilizations out there, by using the transit method, we’ll hopefully embrace most of them, because they’ll also have knowledge of the transit method. The situation in which we’re looking at a region of the sky where we can see them in transit and they can see us in transit maximizes our chances of success.”
James Robinson graduated with a materials science degree from the University of Oxford. He gained a background in plasma technology prior to joining Oxford Instruments Nanoscience as a product manager for the company’s ultra-low temperature systems. Responsible for the new Proteox® system, James has developed a vast knowledge of its usability and unique features that makes it an ideal alternative tool for the low-temperature research.
Dr Jie Xiao is currently a laboratory fellow and group leader of the Battery Materials and System Group at the Pacific Northwest National Laboratory. She holds a joint position at the Department of Chemistry and Biochemistry at the University of Arkansas. Xiao is an ECS fellow and serves as the ECS Battery Division secretary. She received her PhD in materials chemistry from the State University of New York at Binghamton. Xiao has been leading research on practical applications and the fundamental study of energy-storage materials and systems, spanning from microbatteries for acoustic fish tags to advanced battery technologies for vehicle electrification and grid-energy storage. She has published more than 100 peer-reviewed journal papers, two book chapters, and holds 17 US patents in the energy-storage research area. Xiao has been a top 1% Clarivate Analytics Highly Cited Researcher since 2017.
