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Scientists added descriptive terms to the existing general Indigenous frog and reptile names to make them specific. Fortunate Mafeta Phaka, Senior Postdoctoral Researcher of herptile-human interactions, North-West University Licensed as Creative Commons – attribution, no derivatives.

Instabilities in viscoelastic fluids: a long story

Many real-life fluids are not Newtonian and have to be modelled with something more complex than a single scalar viscosity. In this talk we will look specifically at dilute polymer solutions. We’ll see some simple models that capture the essential features of their behaviour, and then investigate how the properties of these models affect the stability of channel flow.

The story spans my whole research career so far, from an early theoretical prediction which was later observed in experiments, to a more recent realisation that there is still quite a lot we don’t understand. If time permits I will also discuss the latest place the research has taken me, which is neither viscoelastic nor unstable.

• Speaker: Prof Helen Wilson, University College London
• Friday 02 May 2025, 16:00-17:00
• Venue: MR2.
• Series: Fluid Mechanics (DAMTP); organiser: Professor Grae Worster.

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Metastability Properties of the Earth's Climate: a Multiscale Viewpoint

The ultralow frequency variability of the Earth’s climate features an interplay of typically long periods of stasis accompanied by critical transitions between qualitatively different regimes associated with metastable states. Such transitions have often been accompanied by massive and rapid changes in the biosphere. Multiple transitions between the coexisting warm and snowball climates occurred more than 600 Mya and eventually led to conditions favourable to the development of multicellular life. The coexistence of such states is due to the instability associated with the positive ice-albedo feedback, Yet, this behaviour repeats itself across a wide range of timescales, spatial domains, and physical processes. Building on Hasselmann’s program, we propose here to interpret the time-evolution of the Earth system as a trajectory taking place in a dynamical landscape, whose multiscale features describe a hierarchy of metastable states and associated tipping points. We introduce the concept of climatic Melancholia states, saddle embedded in the boundary between the basins of attraction of the stable climates and explain under which conditions they act as gateways of noise-induced transitions. Using a hierarchy of numerical models, we discuss in detail the dichotomy between warm and snowball climate by bringing together the deterministic and stochastic viewpoint on the related global stability properties. We then discuss the paleoclimatically-relevant case where multiple competing climatic states are present and show the relevance of our angle for interpreting proxy data. Finally, if time allows, we will present some very recent results suggesting that our viewpoint might explain some intriguing aspects of the dynamical features of the tipping points of the Atlantic Meridional Overturning Circulation.

Key References V. Lucarini and T. Bodai, Transitions across Melancholia States in a Climate Model: Reconciling the Deterministic and Stochastic Points of View, Phys. Rev. Lett. 122, 158701 (2019) G. Margazoglou et al., Dynamical landscape and multistability of a climate model, Proc. R. Soc. A.477 210019 (2021) V. Lucarini, M.D. Chekroun, Theoretical tools for understanding the climate crisis from Hasselmann’s programme and beyond, Nature Reviews Physics 5 (12), 744-765 (2023) D. D. Rousseau et al., A punctuated equilibrium analysis of the climate evolution of cenozoic exhibits a hierarchy of abrupt transitions. Sci Rep 13, 11290 (2023) J. Lohmann et al., Multistability and Intermediate Tipping of the Atlantic Ocean Circulation, Sci. Advances 10 DOI : 10.1126/sciadv.adi4253 (2024)

• Speaker: Prof Valerio Lucarini, University of Leicester
• Friday 09 May 2025, 16:00-17:00
• Venue: MR2.
• Series: Fluid Mechanics (DAMTP); organiser: Professor Grae Worster.

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America’s marine protected areas help fish populations thrive. Trump’s plan to open them to industrial fishing may ultimately harm the fishing industry itself. David Shiffman, Faculty Research Associate in Marine Biology, Arizona State University Licensed as Creative Commons – attribution, no derivatives.

Unravelling the complexity of root stem cell niche regulation through multi-scale models

Abstract not available

• Speaker: Dr Monica Garcia Gomez, Assistant Professor, Utrecht University
• Wednesday 30 April 2025, 14:00-15:00
• Venue: Auditorium of Sainsbury Laboratory Cambridge University - 47 Bateman Street and Online (Zoom meeting). Contact events@slcu.cam.ac.uk for meeting joining details.
• Series: Sainsbury Laboratory Seminars; organiser: Sainsbury Laboratory.

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Unravelling the complexity of root stem cell niche regulation through multi-scale models

Abstract not available

• Speaker: Dr Monica Garcia Gomez, Assistant Professor, Utrecht University
• Wednesday 30 April 2025, 14:00-15:00
• Venue: Auditorium of Sainsbury Laboratory Cambridge University - 47 Bateman Street and Online (Zoom meeting). Contact events@slcu.cam.ac.uk for meeting joining details.
• Series: Sainsbury Laboratory Seminars; organiser: Sainsbury Laboratory.

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Unravelling the complexity of root stem cell niche regulation through multi-scale models

Abstract not available

• Speaker: Dr Monica Garcia Gomez, Assistant Professor, Utrecht University
• Wednesday 30 April 2025, 14:00-15:00
• Venue: Auditorium of Sainsbury Laboratory Cambridge University - 47 Bateman Street and Online (Zoom meeting). Contact events@slcu.cam.ac.uk for meeting joining details.
• Series: Sainsbury Laboratory Seminars; organiser: Sainsbury Laboratory.

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Canada needs a biodiversity protection and conservation act that will address current biodiversity decline and prevent future threats. Trevor Swerdfager, Practitioner-In-Residence, Faculty of Environment, University of Waterloo, University of Waterloo Derek Armitage, Professor, School of Environment, Resources and Sustainability, University of Waterloo Licensed as Creative Commons – attribution, no derivatives.

Thermal vortex rings: the vortex dynamics

A thermal is a convective structure generated from a localized buoyancy anomaly, say, released from the surface. Since it evolves into a donuts-shaped vorticity, the vortex ring, it may be more precisely called the thermal vortex ring. Thermals are often considered basic elements of fully-developed convection in astrophysical and geophysical flows, as most vividly visualized by a cauliflower-like structure of cumulus-convective clouds. This talk revisits the problem of the thermal vortex ring from a point of view of the vortex dynamics. More specifically, I present: 1) a modon solution of a thermal vortex ring as an extension of Hill’s vortex; 2) a concise description based on the volume integrals of the vorticity weighted by a power of the distance from the vortex-ring axis; 3) derivation of a classical similarity solution based on it, as well as 4) a development of a closed system based on an explicit simulation. Those investigations as a whole suggest that the thermal vortex ring could be interpreted as a type of two-dimensional turbulence.

• Speaker: Dr Jun-Ichi Yano, University of Reading
• Friday 13 June 2025, 16:00-17:00
• Venue: MR2.
• Series: Fluid Mechanics (DAMTP); organiser: Professor Grae Worster.

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Claims of ‘bringing back’ any species take away focus from proven solutions that can actually fix the extinction crisis. Martín Boer-Cueva, Ecologist and Environmental Consultant, Universidad Autónoma de Madrid Dieter Hochuli, Professor, School of Life and Environmental Sciences, University of Sydney Marco Salvatori, Post-doctoral Researcher in Ecology, University of Florence Peter Banks, Professor of Conservation Biology, School of Life and Environmental Sciences, University of Sydney Licensed as Creative Commons – attribution, no derivatives.

New research found regrowth in Queensland provided valuable habitat after 15 years, on average, with some species benefiting from trees as young as 3 years of age. Hannah Thomas, PhD candidate in Environmental Policy, The University of Queensland Martine Maron, Professor of Environmental Management, The University of Queensland Licensed as Creative Commons – attribution, no derivatives.

Extinction is, for the time being, forever – and a symptom of our global economic system. Rich Grenyer, Associate Professor in Biogeography and Biodiversity, University of Oxford Licensed as Creative Commons – attribution, no derivatives.

Ever since Charles Darwin, scientists have assumed species facing the same problem often evolve similar traits. But that’s not always the case. Isabelle Ng, PhD candidate, College of Science and Engineering, James Cook University Alexandre Siqueira, Vice-Chancellor's Research Fellow, School of Science, Edith Cowan University Licensed as Creative Commons – attribution, no derivatives.

We don’t want to admit it, but our beloved pet dogs do a lot of environmental damage, from killing or terrifying wildlife to emissions from pet food. Bill Bateman, Associate Professor, Behavioural Ecology, Curtin University Lauren Gilson, Research Associate, Behavioural Ecology, Curtin University Licensed as Creative Commons – attribution, no derivatives.

Biosecurity policies may seem onerous and expensive – but they are working to prevent new species from pushing native species out in the Antarctic. Rachel Leihy, Ecologist, Arthur Rylah Institute for Environmental Research Melodie McGeoch, Professor of Ecology, Monash University Steven Chown, Director, Securing Antarctica's Environmental Future and Professor of Biological Sciences, Monash University Licensed as Creative Commons – attribution, no derivatives.

Many native plants are missing from habitats where they should thrive – even in wilder areas. Why? Human actions such as logging, poaching and setting fires. Cornelia Sattler, Research Fellow in Ecology, Macquarie University Julian Schrader, Lecturer in Plant Ecology, Macquarie University Licensed as Creative Commons – attribution, no derivatives.

Flies are the most ecologically diverse and important migrant group. We just had no idea. Will Hawkes, Insect Migration Researcher, College of Life and Environmental Science, University of Exeter Licensed as Creative Commons – attribution, no derivatives.

External Seminar - Jenn Brophy TBC

Abstract not available

• Speaker: Jenn Brophy, Stanford University
• Wednesday 21 October 2026, 14:00-15:00
• Venue: Auditorium of Sainsbury Laboratory Cambridge University - 47 Bateman Street and Online (Zoom meeting). Contact events@slcu.cam.ac.uk for meeting joining details. .
• Series: Sainsbury Laboratory Seminars; organiser: Sainsbury Laboratory.

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External Seminar - Jenn Brophy TBC

Abstract not available

• Speaker: Jenn Brophy, Stanford University
• Wednesday 21 October 2026, 14:00-15:00
• Venue: Auditorium of Sainsbury Laboratory Cambridge University - 47 Bateman Street and Online (Zoom meeting). Contact events@slcu.cam.ac.uk for meeting joining details. .
• Series: Sainsbury Laboratory Seminars; organiser: Sainsbury Laboratory.

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External Seminar - Jenn Brophy TBC

Abstract not available

• Speaker: Jenn Brophy, Stanford University
• Wednesday 21 October 2026, 14:00-15:00
• Venue: Auditorium of Sainsbury Laboratory Cambridge University - 47 Bateman Street and Online (Zoom meeting). Contact events@slcu.cam.ac.uk for meeting joining details. .
• Series: Sainsbury Laboratory Seminars; organiser: Sainsbury Laboratory.

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