Birth mode, crow memory, quantum navigation: Cambridge science in a Naked Scientists episode

Summary

The Naked Scientists episode surveys a set of Cambridge led science stories spanning health, cognition, physics, and climate. It opens with a study from Cambridge and Fudan University showing that the first dose of the measles vaccine is less effective in infants born by cesarean section than in those born vaginally, possibly due to differences in the early gut microbiome. A second vaccine dose remains protective for most individuals, but the finding highlights that early life factors can shape vaccine responses. The program then explores Eurasian jay cognition, revealing that jays encode incidental details of past events in a way that mirrors some elements of human episodic memory. The show also covers a quantum navigation breakthrough based on cold atom interferometry aimed at providing jam-proof positioning when GPS is unavailable. A tree-ring based climate reconstruction argues that the summer of 2023 was the warmest in roughly two millennia, providing long term context for recent warming. Finally, a cosmology discussion and a coffee foam query round out the episode with expert insights and open questions.

• Measles vaccine response linked to birth mode and gut microbiome
• Eurasian jays display incidental memory similar to episodic memory
• Quantum navigation using cold atom interferometry aims to resist GPS jamming
• Tree rings suggest 2023 summer was the warmest in 2000 years

Birth mode and measles vaccine response

The first major segment presents a study led by researchers at the University of Cambridge and Fudan University in China. They followed a birth cohort from birth and tracked measles vaccination timing and antibody responses over time. By measuring protection against measles in the blood, the researchers identified a higher rate of first dose vaccine failure among babies born via cesarean section compared with those born vaginally. Henrik Salje and colleagues propose that early life gut microbiome differences, shaped by the mode of delivery, may influence how the immune system matures and responds to vaccination. The discussion emphasizes that while maternal antibodies and timing of vaccination are important, the effect observed in cesarean-born infants appears to be distinct from maternal antibody interference. The team notes that in countries like the UK and China, two vaccine doses are standard, and those who fail the first dose often respond to the second dose, a pattern consistent with known vaccination strategies. The potential policy implications include re-evaluating vaccination timing for children born by cesarean section to optimize early immune maturation, especially given rising cesarean rates in some regions. The study appears in Nature Microbiology, highlighting that what might be viewed as a modest difference could have meaningful public health implications for measles control and vaccine strategies more broadly.

The segment also addresses broader questions about how vaccines work in early life, including the role of maternal antibodies that wane over time and can temporarily blunt vaccine efficacy. The researchers stress that the observed effect is not a terminal barrier to immunity. Rather, it suggests that achieving robust protection may require a combination of timing, dosing, and host-microbiome factors. The discussion ends with a note of cautious optimism: even if a subset of individuals show reduced first-dose protection, two-dose regimens generally preserve population immunity, and more research is needed to uncover the precise microbial or developmental mechanisms behind the difference observed between delivery routes.

Eurasian jays and episodic memory

The program then shifts to Cambridge for a study on Eurasian jays memory and cognition. Clare College hosts Nicky Clayton, who explains episodic-like memory in birds. The researchers aimed to test whether jays could remember incidental details of past events, not just the core information about what happened, where, and when. In the experiments, birds hid foods in cups with patterns and colors that are incidental rather than central to the task, and later were queried about those incidental details. The aim was to determine whether jays encode episodic-like memories that include incidental information such as the jumper color or the cup pattern. The findings suggest that jays store personal past experiences in a way that resembles human episodic memory and that their cognitive toolkit is remarkably sophisticated given their brain size relative to body mass. Clayton and colleagues emphasize that corvids, including jays, ravens, crows, and magpies, display cognitive feats such as prospective planning, theory of mind-like reasoning, and episodic memory—the прозess of memory that integrates past experiences with an eye toward future outcomes. The researchers describe these birds as feathered apes in terms of cognitive capabilities, reinforcing the view that some avian species possess complex mental representations comparable in some respects to primates.

Quantum navigation and cold atom interferometry

In a segment on navigation technology, Ramsey Faragher explains how modern GPS depends on signals from satellites and the timing information those signals carry. He describes vulnerabilities to jamming, spoofing, and signal disruption in environments such as tunnels. The Naked Scientists discuss inertial navigation systems that bridge GPS outages using accelerometers and gyroscopes. The show outlines that quantum navigation employs cold atom interferometry to achieve unprecedented sensitivity in measuring accelerations and rotations. The atoms, cooled to near absolute zero, behave as waves and create high precision interference patterns that form the basis for accurate inertial sensing. The technology is still being developed, with engineering challenges such as dynamic range and robustness in high dynamics. The goal is to create tabletop or shoebox sized devices that can provide reliable navigation in GPS-denied environments, including military applications. The segment highlights the collaboration and progress in this cutting edge field, while acknowledging that practical deployment will require addressing engineering hurdles and integrating with conventional inertial navigation systems.

Climate history from tree rings

Ulf Bundtgen and colleagues from Cambridge use tree rings and relic wood to reconstruct climate over two millennia. They describe how tree rings capture growth conditions, with wide rings indicating favorable summers and narrow rings suggesting stress, such as heat and drought. The team explains that they combine multiple trees to reduce noise and calibrate the rings against instrument records to convert ring width into temperature signals. Their analysis shows that the Northern Hemisphere summer of 2023 was roughly 2 degrees Celsius warmer than the preindustrial period, a signal that places recent warmth in a broader geological context. The study emphasizes that while many factors influence tree growth, correlations across regions and overlapping proxies strengthen the case for interpreting ring-width variability as climate signal. The results are reported in Nature, underscoring the importance of long term climate context for understanding anthropogenic warming and its trajectory over centuries.

Does physics change across the cosmos and a foam question

The podcast then turns to a theoretical discussion with Toby Wiseman from Imperial College London about whether the laws of physics could vary in different parts of the universe. He emphasizes the cosmological principle that the large-scale properties of the universe are uniform and isotropic, and that our current framework for physics—encompassing standard model particle physics and general relativity—has successfully described the universe from the earliest moments after the Big Bang to the present. Wiseman describes the idea of physics as a set of discovered principles rather than human constructs, and explains that inflationary fluctuations seed cosmic structures in a way that has repeatedly proven predictive. The segment frames the philosophical question of whether other civilizations might have a deeper understanding of physical laws but notes that the laws themselves would remain the same if the theory is valid across the cosmos.

In the final science question about cappuccino foam, the discussion centers on how milk foam is formed by denatured proteins forming a stable network, and how heating can create a skin on heated milk. The exchange highlights the interplay of proteins and fats in foam formation, referencing common kitchen observations and inviting listeners to contribute their own experiences to the forum.

Closing notes

The Naked Scientists closes with acknowledgments of institutional support from the Institute of Continuing Education at Cambridge, sponsorships from Rolls Royce, and music by Epidemic Sound. Viewers are invited to submit questions and join the discussion on the forum, with a teaser that the next episode would explore artificial intelligence and its capabilities and limits.