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Finding a way to belong: impostor syndrome and mental health

Photo of Belinda Cheeseboro in the Smithsonian Museum's Hall of Flight — **Rightful place** PhD student Belinda Cheeseboro offers advice on how to overcome impostor syndrome in physics. (Courtesy: Belinda Cheeseboro)

“I am not who they think I am.”

When my impostor syndrome flares up, I’m constantly afraid that I will be “exposed” for who I truly am, and then excommunicated from physics for not being “one of them”. These thoughts started to creep in when I was taking my first real physics class as an undergraduate. I wasn’t doing well on the exams and I was struggling with the homework. I started to think, “Can I really do this? Am I meant to be here?”

At that time, I thought that if you’re meant to follow a certain path, then it should come naturally to you. But physics definitely didn’t come naturally to me, so why did I stay in it? Why didn’t I just quit and pick a different field? Well, the first reason is that I am a really stubborn person. When I say I want to do something, I will do it, because I feel I need to prove the people wrong who said I couldn’t. The second reason is that I love science, especially physics. Physics is the subject that satisfies my curiosity and allows me to ask the many questions that run through my mind. How could I not want to pursue it?

Overcoming hardships

When I was a senior in high school, I told my mathematics teacher that I wanted to study astrophysics. He responded by telling me that physics is really hard. So I knew from the start that it wouldn’t be easy, but I told myself that I could do it as long as I put in the effort. The truth, though, is that physics isn’t just hard. It’s super hard, and it was much harder for me than I thought it would be. That’s when I started to have doubts about whether I was a good fit.

I also had a couple of added challenges. The first challenge was that I wasn’t very good at mathematics. In high school I took most of my mathematics classes through an online platform and essentially learned nothing for two years. After that, I spent a year not taking any mathematics at all because I was supposedly “ahead” and couldn’t take the next class because it didn’t fit in my schedule. So when I took a placement exam at the beginning of my undergraduate degree, I was shocked to find that I scored well enough to start calculus right away. I honestly felt like this was a mistake, but I decided to go ahead because I didn’t want to fall behind. Fortunately, my mathematics and physics professors were patient with me even though I struggled so much in their classes.

My other added challenge was more personal. My father passed away during my junior year of high school, and afterward things became difficult for me, my mother and my younger brother. I didn’t give myself time to address my grief because I felt I had to step up and take care of my family; I couldn’t waste time feeling sad and vulnerable. I also felt that my family needed me to succeed, even though they never told me so. All of this took a toll on my mental health, and four years later, during my junior year of undergrad, the effects of never addressing my father’s death finally reached a breaking point. I sought help through therapy, and although I didn’t find it super useful, it did give me tools to help me grieve by writing letters to my father and allowing myself to feel sadness. If I hadn’t done that, I think I would have completely broken down.

The next transition

By the time I finished my undergrad I was starting to feel more confident. I still had doubts about certain aspects of my physics ability, but I had stopped questioning whether I belonged in the field. I truly felt like I was a physicist, and that was due to the wonderful support of the faculty at my undergrad institution. I also found that pressure from my family fuelled my desire to keep going and do well in my chosen path. My loved ones sacrificed so much for me to get where I am today that I simply couldn’t give up, even if I wanted to.

I didn’t do all that well on my physics and general GREs (the entrance exam for postgraduate studies in the US), so I was very surprised when I got accepted into a few PhD programmes. I was even more shocked when I got a fellowship offer from one of them. After visiting a couple of institutions and deliberating over the pros and cons, I settled on West Virginia University (WVU) in part because, out of all the institutions that accepted me, WVU was the closest to my family, and that was very important to me.

Upon entering grad school, I quickly realized that it was more difficult than I thought it would be. (Does this pattern seem familiar?) Between juggling coursework and dipping my feet into research, I was struggling. This was also my first time living by myself, so I felt lonely and isolated. The pressure to do well grew exponentially, and the voice of impostor syndrome, once whisper-quiet, came in like a loud roar: “Are you sure you can do this? Everyone else is doing fine, so why are you struggling so hard? If you keep messing up, people will figure out that you’re not meant to be here.”

During my first year of grad school, these thoughts were in my mind day in and day out. After that, though, I started to socialize with people more, and I realized I was not the only one who was struggling with my classes. I gained comfort from the fact that I was not alone, even though it sometimes felt like it.

The pressure to do well grew exponentially, and the voice of impostor syndrome, once whisper-quiet, came in like a loud roar

Unfortunately, the research side was a different story, because my first adviser made me feel like I was not a good researcher. Often, our conversations centred on how I wasn’t doing enough or putting the time into my work. He would even compare me to his other students and tell me how they were making so much more progress. This meant that I was constantly comparing myself to others, which is a major driving force for impostor syndrome because it makes you feel like you shouldn’t be there. As a result, I became depressed, and I started to lose both my passion for research and my motivation to do well. I even started to question why I was in grad school and whether it mattered if I got a PhD.

After I was forced to leave this first research group, I participated in a summer internship as a way of escaping my toxic situation. Sometimes, it helps to place yourself in a safer, more positive environment for a while, and my internship gave me that refuge. When I returned, though, I was immediately thrown into the cycle of impostor syndrome again, because switching advisers would have meant that I had to take on a new research project. At this point, I knew I needed to seek mental health counselling. Reluctantly, I scheduled some one-on-one sessions at our student counselling centre, and those sessions helped me address the trauma I experienced.

The disability is there, but I belong

Facing problems

Earlier in my academic journey, I became accustomed to running away from my problems because I thought if I took the time to address them and take care of my mental health, I would “fall behind” everyone else. Since then, I’ve learned that the opposite is true: avoiding problems and not addressing trauma is actually a great way to make your mental health worse. It also fuels impostor syndrome because you’re “not being productive like everyone else”. The first step to achieving mental wellness, therefore, is to acknowledge the problems you’re facing. By doing that, you give yourself space to work through whatever emotions you’re experiencing.

My impostor syndrome constantly told me that I was not like everyone else; that I couldn’t succeed; that my accomplishments were small in comparison to those of my peers; and that I shouldn’t be held up on the same pedestal as them. In fact, none of these things is true. We are all on different paths, so it doesn’t make sense to compare yourself to others, even if they look like you. Taking care of your mental health and combating feelings of impostor syndrome takes time, but it can be done. Ultimately, my path is my own, and however long it takes me to traverse it is up to me.

Celebrating Black physicists

This week is #BlackInPhysics week, a series of events dedicated to celebrating Black physicists and their contributions to the scientific community. In this episode of the podcast, we talk to two of the week’s co-organizers, Ashley Walker and Xandria Quichocho, about what #BlackInPhysics week involves, why it’s needed and what they hope to achieve.

Walker and Quichocho also discuss their own careers and experiences. Neither followed a traditional path into physics – Walker started out studying business, while Quichocho’s first interest was in music education – but they are now deeply immersed in the field, as a planetary astrochemist at the NASA Goddard Space Flight Center and a PhD student in physics education at Michigan State University, respectively. “We’re here, we’re doing stuff and we’re an active part of the science community,” Quichocho says. “We want to show that it’s okay to be a Black physicist, it’s okay to be a Black scientist,” Walker adds. “We want to show more visibility so that children can know that we exist.”

LIGO–Virgo announces ‘bumper crop’ of gravitational-wave detections

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.

Black hole versus neutron star

Most of the 39 new signals appear to come from the merger of two black holes, but the haul also includes the second signal ever received from a pair of merging neutron stars (“LIGO–Virgo claims another neutron-star merger”) and also what could be the first ever signal from the merger of a black hole and a neutron star (“Black-hole–neutron-star merger may have been spotted by LIGO–Virgo”).

Also included in the 39 is the gravitational-wave signal from the most massive merger of two black holes ever seen (“LIGO–Virgo spots its most massive black hole merger so far”). This was the topic of a Physics World Weekly podcast in September that featured gravitational-wave expert Laura Nuttall (“Why that massive black-hole merger is important…”).

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 papers are available on the LIGO website.

Do colliding neutron stars or supernovae produce heavy elements?

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.

Proteox5mK: Low electron temperatures for new materials characterization

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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.

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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.

Electrochemistry in rechargeable lithium metal batteries

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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.

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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.

The disability is there, but I belong

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.

Graphene oxide microbubbles are near-perfect microlenses

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.

The research is described in Advanced Photonics.

Could hydrogen peroxide generation underlie mini- and micro-beam radiotherapy efficacy?

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.

Temporal diffusion — 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 H₂O₂distribution 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.

In the experiment that did not reach the minimum beam-on time, the model predicted that H₂O₂did 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 H₂O₂diffused uniformly over the target, produced five tumour ablations out of 11 rats.

The researchers surmise therefore that homogeneous H₂O₂distribution 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 H₂O₂coverage 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.

US heads to the polls in an election focused on science

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 Post reported 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.”

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