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Research team from Goethe University and TU Munich involved
Extremely dense neutron stars may contain unstable hyperons in their interior, which, like the stable hadrons of the atomic nucleus, protons and neutrons, are held together by the strong interaction. Scientists from the ALICE collaboration at the accelerator centre CERN have now developed a method to precisely measure the strong interaction between unstable hadrons in experiments for the first time. Research teams from Goethe University headed by Professor Harald Appelshäuser and TU Munich headed by Professor Laura Fabbietti were involved in the development.
FRANKFURT. In an article published today in Nature, the ALICE collaboration describes a novel method that will allow precision measurements of the strong interaction between hadrons at the Large Hadron Collider (LHC) accelerator at CERN in Geneva.
Hadrons - which include protons and neutrons - are particles composed of two or three quarks, which are held together by the strong interaction. However, the interaction is not limited to the interior of the hadron, but extends beyond it. It leads to something known as residual interaction, due to which hadrons also exert forces on each other. The best-known example is the force between protons and neutrons, which is responsible for the cohesion of atomic nuclei. One of the great challenges of modern nuclear physics is to achieve an accurate calculation of the strong force between hadrons, which is based on the underlying strong interaction of quarks.
Within the framework of something known as "lattice QCD" calculations, the effective strong force between hadrons can be calculated on the basis of the fundamental theory of the strong interaction between quarks. However, these calculations are only very accurate for hadrons containing heavy quarks. This applies, for example, to hyperons, i.e. hadrons that contain one or more strange quarks. Although the strong interaction caused by collisions of hadrons can be studied in scattering experiments, it is difficult to perform these experiments with unstable hadrons such as hyperons. Accordingly, an experimental comparison with the precise theoretical predictions from the lattice QCD for hyperons is difficult.
In today's publication of the ALICE collaboration a method is presented which allows the study of the dynamics of the strong interaction for arbitrary pairs of hadrons. This concerns especially those hadrons which are short-lived, i.e. which decay after fractions of seconds and therefore cannot be investigated in scattering experiments. Instead, the hadrons are generated in proton-proton collisions at the LHC. The interaction between them can be measured on the basis of their relative momentum distribution.
Professor Laura Fabbietti from the TU Munich, who has contributed significantly to the results presented here, emphasises that this breakthrough is due to both the LHC and the ALICE detector. The LHC is able to generate a very large number of hadrons with strange quarks and thus provides an insight into the nature of the strong interaction. The ALICE detector and its high-resolution Time Projection Chamber (TPC), in turn, would provide the necessary precision to identify the particles accurately and measure their momentum accurately.
Harald Appelshäuser, professor at Goethe University, has been leading the ALICE TPC project for ten years and is co-author of the publication. He works closely with Laura Fabbietti's Munich group and emphasises that the method presented would usher in "a new era of precision studies of the strong interaction between exotic hadrons at the LHC."
The method presented is called femtoscopy because the processes examined take place in a spatial area of about 1 femtometre (10-15metres). This corresponds approximately to the size of a hadron and the range of the strong interaction. Using this method, the ALICE collaboration has already been able to study interactions between hyperons containing one or two strange quarks. In today's publication, a measurement of the interaction between a proton and the omega (Ω) hyperon has now been investigated for the first time and with high precision. The omega is the rarest of all hyperons and consists of three strange quarks.
Professor Appelshäuser emphasises that the significance of the results goes beyond the verification of theoretical calculations: "Femtoscopic investigations can significantly expand our understanding of very dense stellar objects such as neutron stars, which can contain hyperons in their interior and whose interaction is still largely unknown."
Publication: Shreyasi Acharya et al. (ALICE Collaboration): Unveiling the strong interaction among hadrons at the LHC. Nature, 9. December 2020 – https://doi.org/10.1038/s41586-020-3001-6
Explanatory video by TU Munich on this subject:
Rätselhafte Neutronensterne – Präzise Messung der starken Wechselwirkung - YouTube
Images may be downloaded here:
Caption: In the future, hyperons will be measured at the ALICE detector of the CERN particle accelerator centre. Scientists from Goethe University are part of the ALICE collaboration. Credit: CERN
Prof. Dr. Harald Appelshäuser
Institute for Nuclear Physics
Goethe University Frankfurt
Phone: +49 69 798-47034 or 47023
Geoscientists at Goethe University hope for certainty from asteroid samples from space - sample container safely landed on Saturday evening
On Saturday evening (5.12.2020), a container containing a sample of the asteroid that had been dropped by the Hayabusa 2 space probe landed in the Australian desert. The chemical "fingerprint" of the water from the asteroid Ryugu could prove that the water on Earth actually originated from asteroid impacts in the early history of the Earth. Up to now, asteroids could only be examined after fragments impacted onto the Earth and therefore contamination by the Earth's water could not be ruled out. In the coming year, the material sample will be examined by scientists all over the world, including a scientific team from Goethe University.
FRANKFURT. When it was formed, the young proto-Earth was hot and probably circled around the sun in a very dry zone where water evaporated and was blown into space by the solar wind. According to one theory, our blue planet came to its great oceans through watery celestial bodies that hit the earth. As spectral analyses of comet tails have shown, it was most likely not comets.
This is because in their ice, the ratio of hydrogen with two protons in its nucleus, deuterium (D), to hydrogen with one proton in its nucleus (H) is usually different from that on Earth. On the other hand, the water trapped in certain meteorites - i.e. in fragments of asteroids that have hit the Earth - is almost exactly the same as terrestrial water. Such C-class asteroids are highly carbonaceous and come from the outer part of the asteroid belt that orbits the sun between Mars and Jupiter. Ryugu is one of them.
Prof. Frank Brenker, geoscientist at Goethe University, will examine the Ryugu sample together with his colleague Dr. Beverly Tkalcec. He explains: "There are very good scientific arguments that the D/H ratio we find in meteorites is indeed similar to that of asteroids in space. Nevertheless, we cannot rule out water vapour contamination on Earth: after all, 90 percent of an asteroid evaporates when it passes through the atmosphere, and even if it hits a dry desert, the meteorite can absorb water until it is found, for example from early morning fog. With the Ryugu sample we will finally get certainty on this issue".
To this end, from the middle of next year, the Frankfurt researchers will examine and screen Ryugu samples for their chemical composition at the particle accelerators ESRF in Grenoble and DESY in Hamburg. Later in the year, Ryugu samples will be cut with the help of a focused ion beam and will be examined with a transmission electron microscope at Goethe University. Tkalcec and Brenker want to determine the exact geological history of the asteroid. In order to be able to assess the measured values for the water, but also the organic compounds that occur, it is immensely important to understand all the processes that led to their formation in the first place. The temperature achieved by the asteroid is just as important here as the circumstances of the formation of water-containing minerals, and the influence of impacts on the surface of the asteroid.
The building blocks for life on Earth may also come from carbon-rich asteroids such as Ryugu, since sugars and components of proteins (amino acids) and the hereditary molecule DNA (nucleobases), which could have been formed from inorganic substances under suitable conditions, have already been found in meteorites. For this reason as well, numerous scientific teams from all over the world will be working on the analysis of the Ryugu samples.
Images for download:
Prof. Dr. Frank Brenker
Institute for Geosciences – Nanoscience
Phone: +49 151 68109472
International research team discovers shifts in small regulatory RNAs
Approval by the German Research Foundation (DFG): CRC 1080 starts its third round
The Collaborative Research Centre 1080 was successful in the German Research Foundation’s current round of approvals and will start its third funding period in 2021. The DFG is providing € 2 million per year for four years of research. In the CRC 1080, scientists from various disciplines investigate how the brain and nervous system maintain stability as a complex system while also remaining accessible and flexible.
FRANKFURT. One of the most remarkable features of our nervous systems is its ability to maintain a stable internal state (homeostasis) while having to constantly respond to an ever-changing environment. In the Collaborative Research Centre 1080, the participating scientists endeavour to understand the significance of homeostatic mechanisms for the human body, in particular for diseases of the nervous system. They investigate mechanisms which enable the brain to maintain network homeostasis as a balanced functional condition. This is decisive for the stability of the nervous system, and helps the brain process the constant flow of input.
The CRC 1080, which started in 2013, has been extended by four years for the second time, so that the funding will continue through to 2024. Goethe University is the coordinator, and the Johannes Gutenberg-Universität Mainz, the Max Planck Institute for Brain Research, the Institute for Molecular Biology in Mainz (IMB) and the Hebrew University of Jerusalem are cooperation partners.
CRC spokesperson Professor Amparo Acker-Palmer says: “The strength of the Collaborative Research Project 1080 is the integration of diverse research disciplines, we are not just looking at individual genes, cell types, pathological processes or structures. Instead, we engage experimental approaches and computer simulations that enable us to follow whole chains of events that lead to neural homeostasis. The Rhine-Main network of neurosciences rmn2, in which we are integrated, provides an optimal environment for the CRC.”
Professor Amparo Acker-Palmer
Spokesperson for CRC 1080
Institute for Cell Biology and Neurosciences
Phone: + 49 69 798-42565
The research project “ZOWIAC“ by Goethe University and the Senckenberg Society for Nature Research will be funded with three fourths of a million euros
The raccoon, raccoon dog, mink and golden jackal are not native to Germany or Europe, but are increasingly spreading in these non-native regions. The joint research project ZOWIAC, “Zoonotic and ecological effects on wildlife of invasive carnivores" by Goethe University and the Senckenberg Society for Nature Research will study how these invasive and alien species threaten biological diversity and which diseases they can transmit to humans as well as animals. The project is mainly funded by the German Federal Environmental Foundation (DBU). The research project will receive additional funding and support from Senckenberg and the regional hunting associations in Hessen and Bavaria, and will also involve nature conservation groups, hunters and citizens.
FRANKFURT. More and more exotic animals and plants are being intentionally and unintentionally introduced into Europe from areas where they naturally occur. In Germany alone, more than one thousand invasive alien species (IAS) are registered. Invasive species cause significant changes to species communities and ecological systems and are considered one of the most important risks to biological diversity. Because they transmit diseases or serve as intermediate hosts for pathogens, they threaten the health of humans as well as pets, livestock and wildlife. The EU Commission estimates the annual economic and health damage caused by IAS in Europe at 9.6 to 12.7 million euros. In the course of globalisation and the increasing population and settlement density, invasive species are also attaining increasing significance in cities.
Among the species that are spreading more and more in Europe are the two predatory mammals raccoon (Procyon lotor) and raccoon dog (Nyctereutes procyonoides), which are considered invasive, as well as the mink (Neovision vison) and the golden jackal (Canis aureus), the latter occurring with increasing frequency in Germany over the last ten years. Due to their broad food spectrum and high adaptability these animals are able to live in almost any natural habitat. They are suspected to be among the factors responsible for the decline of numerous indigenous species, some of which are endangered, such as bats, various amphibian and reptile species, and ground-nesting birds. The project will also investigate whether their moving into urban areas favours the transmission of pathogens to humans and animals, so-called zoonoses.
A zoonosis introduced to Europe by the racoon is the racoon roundworm (Baylisascaris procyonis), whose eggs are spread through the animals' faeces. This poses a potential threat to human health, particularly in cities, where racoons utilise anthropogenic food resources and spaces. Racoons also serve as reservoir hosts for coronaviruses, lyssaviruses (rabies), canine distemper virus, and the West Nile virus. The spectrum of pathogens of the racoon dog resembles that of the racoon. In addition, it is considered the final host of the fox tapeworm (Echinococcus multilocularis). The mink is one of the most widely spread alien mammal species worldwide and is considered a carrier of a variety of zoonoses such as leptospirosis, trichinosis and toxoplasmosis. The golden jackal carries zoonosis pathogens as well. Some of them, such as the canine tapeworm (Echinococcus granulosus), the canine roundworm (Toxocara canis) and trichinae, can have significant effects on public health.
The joint project ZOWIAC will make an essential contribution to the development of up-to-date, sound and reliable data in order to better assess the health risk posed by the raccoon, raccoon dog, mink and golden jackal, and their impact on native species and ecosystems, says project leader Professor Sven Klimpel from Goethe University and the Senckenberg Society for Nature Research. A systematic monitoring of the most frequently associated pathogens will be carried out. Furthermore, spatial aspects will be considered in particular, i.e. established populations in urban and rural regions (agricultural/forestry/bodies of water), populations at their current distribution limits in Europe, as well as from the regions of origin (North America, Asia). Daliy movement patterns can be determined by radio collaring single individuals. Metabarcoding of stomach and faeces samples will provide detailed information on food spectrum and parasite fauna, in order to better estimate possible effects on biodiversity and the zoonosis potential. Various population and environmental parameters will be collected and used to create dispersal models to show the potential distribution and occurrence of these carnivorous mammals also under changing climatic conditions, Klimpel explains further.
Since the future success in mitigating negative effects from IAS will depend largely on public understanding and participation, all relevant groups and actors will be involved. In addition to cooperation partners from the scientific community, hunting associations and relevant ministries, citizens will also be involved in the research project (Citizen Science). As a basis for this exchange, an application and an online communication platform will be developed to generate data and provide information on current research findings. Since ZOWIAC includes aspects on wildlife ecology and health research, the project will also deliver results that can serve relevant ministries and authorities as a basis for decisions on how to handle invasive and alien predators in Germany and Europe.
Images for download:
Caption: Raccoon dog (Nyctereutes procyonoides), Credit: Dorian D. Dörge, Goethe University Frankfurt
Caption: Raccoon (Procyon lotor), Credit: Dorian D. Dörge, Goethe University Frankfurt
Prof. Dr. Sven Klimpel
Chair for Integrative Parasitology and Zoophysiology
Institute of Ecology, Evolution and Diversity
Goethe University Frankfurt
Phone: +49 69 798 42249
Norbert Peter, M.Sc., Dipl.-Forsting. (FH)
Medical Biodiversity and Parasitology
Senckenberg Society for Nature Research
Phone: +49 69 798 42212