14th December 2018 at 14.15 in D101: Ilona Riipinen

Our final colloquium of 2018 will take place on 14th December. Our speaker is physicist and atmospheric scientist Professor Ilona Riipinen from Stockholm University. Her work focuses on understanding the atmospheric processes governing air quality and global climate. She studies various aspects of the atmosphere, in particular mass transfer processes at atmospheric gas-liquid interfaces, focusing on the sources, processing and sinks of ultrafine (less than 100 nm in diameter) aerosol particles. To pin down the effects of aerosols on climate and air quality, the processes governing their concentrations and interactions with clouds need to be understood and represented accurately in large-scale models. The methodologies used range from molecular level simulations to global Earth system modelling.

In her talk, titled How clouds clean the air and influence the climate – and why should you care?, she will tell us a bit about this interesting, and very important work. Here is her abstract:

Clouds are an important component of the Earth’s energy budget. Besides emissions of greenhouse gases, human activities influence the climate through the impacts anthropogenic aerosol particles have on clouds. Understanding the role of aerosols and clouds in the climate system is central for understanding climate sensitivity – i.e. the response of the climate system to different pollutants – and hence designing the actions required for meeting the Paris agreement. In my presentation, I will discuss the future of the Earth’s climate, the role of aerosols and clouds in it, and how it links to the choices we make in our everyday lives.

After the 30 minute talk, there will be a cocktail reception. Welcome!

24th May 2019 at 14.30 in D101: Bergita Ganse

For our colloquium on 24th of May, we will be joined by Dr. Bergita Ganse. Dr. Ganse is a medical doctor, book author and scientist specialising in space medicine, working as a lecturer in space medicine at RWTH Aachen University in Germany. Her research deals with the musculoskeletal system in space, and she is involved in large international studies with both NASA and ESA.

In her talk, titled Space Medicine – Weightlessness and Shrimp Cocktail, she will tell us about the physiological toll that spaceflight places on the human body, and research that is currently underway to mitigate its effects. Here is her abstract:

Human spaceflight is associated with massive challenges to the body and health. While planning missions to Mars, asteroids, moons and other planets of the solar system, health and human physiology are major operational concerns for mission success. Phenomena such as space motion sickness, bone and muscle loss, space adaptation back pain, cardiovascular changes, G-measles, decompression sickness during space walks and the Apollo-15-syndrome need to be addressed to guarantee crew safety. Space Medicine is still a “final frontier” 50 years after the first men walked on the moon.

This talk will give an overview of the field of space medicine with regards to medical and physiological issues connected to human space flight. It will also give an insight into research methods used in space medicine, such as bed rest studies, human centrifugation and parabolic flights. In addition, it will explain why Shrimp Cocktail is the favourite dish on board the International Space Station.

This colloquium is organised jointly with the HIP seminar series, and will follow the talk given by Physics Nobel Prize winner Frank Wilczek, starting at 13:15 in the same room, D101. His talk is titled Axion plasmon converter. More information can be found on the HIP seminar webpage.

At 15:00, there will be a cocktail reception. Welcome!

16th November 2018 at 14.15 in D101: Michael Ramsey-Musolf

Our next colloquium will be on Friday 16th November. Our speaker is an internationally renowned particle physicist, Professor Michael Ramsey-Musolf from UMass Amherst. Michael is also director of the Amherst Center for Fundamental Interactions. He is known for his advocacy for the LGBTQ community in physics. He is a co-author of the Best Practices Guide for LGBT+ Inclusivity in Physics and Astronomy, jointly developed by the lgbt+physicists and the AAS Committee for Sexual and Gender Minorities in Astronomy. In his colloquium talk this week, titled Shattering the Lavender Ceiling: A Gay Theoretical Physicist’s Perspective, he will share his own insights as well as discuss some positive actions we can take as a community. Here is his abstract:

Science advances most effectively when the scientific community embraces and supports scientists from all backgrounds and identities. In this talk, I focus on the particular challenges to full inclusion in the scientific enterprise faced by LGBTQ physicists – the “lavender ceiling”. I will share insights from my own experience as an out gay theoretical physicist and from a recent American Physical Society climate study. I will also highlight some “best practices” that a physics department may adopt to engender a more inclusive climate for sexual and gender minorities.

After the 30 minute talk, there will be a cocktail reception. Welcome!

Update 27.11.2018: You can watch a video of Michael’s talk here:

26th October 2018 at 14.15 in D101: Simo Huotari

Our next colloquium will be held on 26th October. Our next talk is by another new professor in our department, Simo Huotari.

Simo is a Professor in Experimental Materials Physics here in Helsinki.  He has made an international  career in the use of synchrotron light for materials research, having most notably worked 7 years at ESRF – The European Light Source. In his talk, titled Let there be light: X-rays for life sciences, mathematics, cultural heritage, energy, health, and environment, he will tell us about his research. Here is what he has to say about his research and the colloquium talk:

Solutions to many of the crucial challenges facing humanity, such as developing alternative sources of energy, improving health, mitigating environmental and climate problems and developing new green economies, depend on the detailed understanding of the constitution of matter and on the molecular and electronic control of processes that determine the function of materials and biological systems.

X-rays offer a light for insights in both basic and applied research, covering virtually all fields of science from physics, chemistry, and biology, to energy, medicine, cultural heritage, environmental sciences, medical physics and engineering.

The brighter the light, the better the vision. The large-scale light sources such as synchrotrons and  x-ray free electron lasers (XFEL) have seen an exponential growth of brilliance that magnificiently outruns even Moore’s law. They are giant microscopes, which enable research on materials  in the tiniest detail, helping make invisible information strikingly visible.

For example, the world’s most powerful x-ray laser is now in operation in Hamburg. The 3.4-km long European XFEL produces light in <100-fs short pulses and its light drills a hole in a 5-cm thick piece of steel in a matter of seconds. The extremely powerful  laser strips the target’s atoms from electrons, resulting in Coulomb explosion and forming hot dense plasma, giving access to the  studies of transient behavior of matter in extreme conditions such as in warm dense matter found in cores of giant planets. As an ultrafast probe, XFEL gives access to fs-scale dynamics in materials and has great potential for imaging of single molecules.

On a local and less destructive level,  the X-ray Laboratory at the University of Helsinki works together with all four campuses of the University, many national facilities and organisations such  as VTT, Finnish Environment Institute (Suomen Ympäristökeskus, SYKE),  National Resources Institute Finland (Luonnovarakeskus, LUKE), and  Natural History Museum (Luonnontieteellinen museo, LUOMUS).

The X-ray Laboratory is an integral part of the Helsinki Institute of Life Science through the Helsinki In-vivo Animal Imaging Platform.

In this colloquium, an overlook to novel aspects of this exponentially growing field is given and the entirely new possibilities given by new emerging light sources are discussed.

After the 30 minute talk, there will be a cocktail reception. Welcome!

Update 8.11.2018: Simo’s slides are available to download here.

7th September 2018 at 14.15 in D101: Samuli Siltanen

Our first colloquium of the new academic year will be held on 7th September. The speaker is Samuli Siltanen, Professor of Industrial Mathematics here in Helsinki. He is an expert in inverse problems, particularly as applied to medical imaging

We think that his work will be of great interest to physicists too – as it has connections with physics in a variety of ways, ranging from the imaging technologies on which it relies through to the mathematical techniques employed in his work. His talk, titled Three-dimensional X-ray vision by sparse tomography, will introduce us to his latest research.

Here is the abstract:

Traditional X-ray tomography is used routinely in hospital CAT-scans and in industrial non-destructive testing. There the idea is to collect a large number of X-ray projection images from all around the object, interpret the data as line integrals over a non-negative X-ray attenuation coefficient function, and reconstruct the inner structure of the target. Typically, the reconstruction algorithm of choice is some variant of Filtered Back-Projection (FBP). However, in many practical applications there are radiation dose restrictions or geometric obstacles preventing the collection of a comprehensive dataset. In such cases the FBP algorithm does not perform optimally. In recent years there has been tremendous progress in the development of robust reconstruction algorithms for sparse-data tomography. One of the successful approaches is variational regularization with a sparsity constraint; this approach is closely related to compressed sensing. The new algorithms open up novel imaging possibilities in the fields of dental imaging, welding inspection, adaptive optics in telescopes and environmental monitoring. Changing the physics does not necessarily change the mathematics of reconstruction, so the methods apply as well to electron tomography, neutron tomography and more.

After the 30 minute talk, there will be a cocktail reception. Welcome!

Update 10.9.2018: Samuli’s slides are available to download here.