Press releases

The police – your friend and helper? For people immigrating into Europe from another country, this is not always the case. A study at Goethe University shows how the relationship to state power develops among different immigrant groups.  

FRANKFURT. The murder of African-American George Floyd in May 2020 led to worldwide protests against police violence. Not least because of these developments, in Europe, too, the relationship between the police and ethnic minorities has been a hotly debated topic in the recent past. 

A study by Christian Czymara of Goethe University Frankfurt and Jeffrey Mitchell of Umeå University (Sweden), which has just been published, also focuses on the trust placed in the police by immigrants in Europe. The two social scientists have analysed the data of almost 20,000 immigrants from 22 European countries in the period from 2006 to 2019. These data, which originate from the European Social Survey, show that trust in the police is indeed on average higher among immigrants than among the native population. However, the longer people live in the destination country, the more trust tends to erode. 

The European Social Survey asks interviewees about their trust in various institutions, which they rank on a scale of 0 to 10. Over half the interviewees originally come from other European countries, 12 percent from Africa, 25 percent from Asia. 

The authors have two explanations for the fact that trust decreases with the length of stay: first, the memory of the country of origin, and of the situation there, fades. The contrast between the country of origin and the country of destination is particularly significant for people who have immigrated from countries with a lower level of rule of law to a country that is very advanced in that respect. The second explanation is that these people often experience discrimination in their new surroundings, especially those belonging to an ethnic minority there. This is indicated by the fact that the effect of people's experiences of discrimination is stronger for those who have been in the destination country for longer than for those who have recently arrived. Moreover, comparisons between European countries clearly demonstrate that trust is on average lower where there are more police – for example, in Cyprus, Croatia and Greece. The authors conclude that the size of a police force alone can hardly boost trust in the police, but instead experiences of discrimination must be reduced. Accordingly, efforts in this area would help to maintain the high level of trust in the police among new immigrants and to restore the trust of those who have lived in their host country for a long time.

Publication: Czymara & Mitchell (2022). All Cops are Trusted? How Context and Time Shape Immigrants' Trust in the Police in Europe. Ethnic and Racial Studies. https://www.tandfonline.com/doi/full/10.1080/01419870.2022.2060711

Further information
Dr Christian Czymara
Research Associate
Institute of Sociology
Goethe University Frankfurt
Tel.: +49 69 798 36708
czymara@soz.uni-frankfurt.de
https://www.fb03.uni-frankfurt.de/74691200/czymara

Astronomers have unveiled the first image of the supermassive black hole at the centre of our own Milky Way galaxy. This result provides overwhelming evidence that the object is indeed a black hole and yields valuable clues about the workings of such giants, which are thought to reside at the centre of most galaxies. The image was produced by a global research team called the Event Horizon Telescope (EHT) Collaboration, using observations from a worldwide network of radio telescopes. Theoretical Physicists from Goethe University Frankfurt were instrumental in interpreting the data.

FRANKFURT. The image is a long-anticipated look at the massive object that sits at the very centre of our galaxy. Scientists had previously seen stars orbiting around something invisible, compact, and very massive at the centre of the Milky Way. This strongly suggested that this object — known as Sagittarius A* (Sgr A*, pronounced "sadge-ay-star") — is a black hole, and today's image provides the first direct visual evidence of it.

Although we cannot see the black hole itself, because it is completely dark, glowing gas around it reveals a tell-tale signature: a dark central region (called a “shadow") surrounded by a bright ring-like structure. The new view captures light bent by the powerful gravity of the black hole, which is four million times more massive than our Sun.

“We were stunned by how well the size of the ring agreed with predictions from Einstein's

theory of general relativity," says EHT Project Scientist Geoffrey Bower from the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei. “These unprecedented observations have greatly improved our understanding of what happens at the very centre of our galaxy and offer new insights on how these giant black holes interact with their surroundings."

Because the black hole is about 27,000 light-years away from Earth, it appears to us to have about the same size in the sky as a donut on the Moon. To image it, the team created the powerful EHT, which linked together eight existing radio observatories across the planet to form a single “Earth-sized" virtual telescope [1]. The EHT observed Sgr A* on multiple nights, collecting data for many hours in a row, similar to using a long exposure time on a camera.

The enormous amount of observational data collected had to be interpreted theoretically. For this, a research team led by theoretical astrophysicist Luciano Rezzolla from Goethe University Frankfurt used supercomputers to simulate how a black hole could look like when observed by the EHT – based on what had already been known about Sgr A*. In this way, the scientists created a library of millions of images. Then, they compared this  image library with the thousands of different images of the EHT to deduce the properties of Sgr A*.

The breakthrough follows the EHT Collaboration's 2019 release of the first image of a black hole, called M87*, at the centre of the more distant Messier 87 galaxy.

The two black holes look remarkably similar, even though our galaxy's black hole is more than a thousand times smaller and less massive than M87* [2]. “We have two completely different types of galaxies and two very different black hole masses, but close to the edge of these black holes they look amazingly similar," says Sera Markoff, Vice Chair of the EHT Science Council and a professor of theoretical astrophysics at the University of Amsterdam, the Netherlands. “This tells us that general relativity governs these objects up close, and any differences we see further away must be due to differences in the material that surrounds the black holes."

This achievement was considerably more difficult than for M87*, even though Sgr A* is much closer to us. EHT scientist Chi-kwan ('CK') Chan, from Steward Observatory, the Department of Astronomy and the Data Science Institute at the University of Arizona, US, explains: “The gas in the vicinity of the black holes moves at the same speed — nearly as fast as light — around both Sgr A* and M87*. But where gas takes days to weeks to orbit the larger M87*, in the much smaller Sgr A* it completes an orbit in mere minutes. This means the brightness and pattern of the gas around Sgr A* was changing rapidly as the EHT Collaboration was observing it — a bit like trying to take a clear picture of a puppy quickly chasing its tail."

The researchers had to develop sophisticated new tools that accounted for the gas movement around Sgr A*. While M87* was an easier, steadier target, with nearly all images looking the same, that was not the case for Sgr A*. The image of the Sgr A* black hole is an average of the different images the team extracted, finally revealing the giant lurking at the centre of our galaxy for the first time.

The effort was made possible through the ingenuity of more than 300 researchers from 80 institutes around the world that together make up the EHT Collaboration. In addition to developing complex tools to overcome the challenges of imaging Sgr A*, the team worked rigorously for five years, using supercomputers to combine and analyse their data, all while compiling an unprecedented library of simulated black holes to compare with the observations.

Luciano Rezzolla, professor of Theoretical Astrophysics at Goethe University Frankfurt, explains: “The mass and distance of the object were known very precisely before our observations. We thus used these tight constraints on the size of the shadow to rule out other compact objects – such as boson stars or wormholes – and conclude that: 'What we're seeing definitely looks like a black hole!'"

Using advanced numerical codes, theorists in Frankfurt have performed extensive calculations on the properties of the plasma accreting onto the black hole. Rezzolla: “We managed to calculate three million synthetic images varying the accretion and radiation emission models, and considering the variations seen by observers at different inclinations with respect to the black hole."

This last operation was necessary because the image of a black hole can be radically different when seen by observers at different inclinations. “Indeed, a reason why our images of Sgr A* and M87* are rather similar is because we're seeing the two black holes from an almost identical angle," Rezzolla explains.

“To understand how the EHT has produced an image of Sgr A* one can think of producing a picture of a mountain peak based on a time-lapse video. While most of the time the peak will be visible in the time-lapse video, there are times when it is not because it is obscured by clouds. On average, however, the peak is clearly there. Something similar is true also for Sgr A*, whose observations lead to thousands of images which have been collected in four classes and then averaged according to their properties. The end result is a clear first image of the black hole at the centre of the Milky Way." Rezzolla concludes.

Scientists are particularly excited to finally have images of two black holes of very different sizes, which offers the opportunity to understand how they compare and contrast. They have also begun to use the new data to test theories and models of how gas behaves around supermassive black holes. This process is not yet fully understood but is thought to play a key role in shaping the formation and evolution of galaxies.

“Now we can study the differences between these two supermassive black holes to gain valuable new clues about how this important process works," says EHT scientist Keiichi Asada from the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei. “We have images for two black holes — one at the large end and one at the small end of supermassive black holes in the Universe — so we can go a lot further in testing how gravity behaves in these extreme environments than ever before."

Progress on the EHT continues: a major observation campaign in March 2022 included more telescopes than ever before. The ongoing expansion of the EHT network and significant technological upgrades will allow scientists to share even more impressive images as well as videos of black holes in the near future.

To Goethe University are associated a number of scientists in the EHT Collaboration. Together with Professor Luciano Rezzolla, Dr Alejandro Cruz Orsorio, Dr Prashant Kocherlakota and Kotaro Moriyama, also Prof Mariafelicia De Laurentis (University of Naples), Dr Christian Fromm (University of Würzburg), Prof Roman Gold (University of Southern Denmark), Dr Antonios Nathanail (University of Athens), and Dr Ziri Younsi (University College London) have provided essential contributions to the theoretical research in the EHT Collaboration.

This work has been supported by the European Research Council.

Notes:

[1] The individual telescopes involved in the EHT in April 2017, when the observations were conducted, were: the Atacama Large Millimeter/submillimeter Array (ALMA), the Atacama Pathfinder Experiment (APEX), the IRAM 30-meter Telescope, the James Clerk Maxwell Telescope (JCMT), the Large Millimeter Telescope Alfonso Serrano (LMT), the Submillimeter Array (SMA), the UArizona Submillimeter Telescope (SMT), the South Pole Telescope (SPT). Since then, the EHT has added the Greenland Telescope (GLT), the NOrthern Extended Millimeter Array (NOEMA) and the UArizona 12-meter Telescope on Kitt Peak to its network.
ALMA is a partnership of the European Southern Observatory (ESO; Europe, representing its member states), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan, together with the National Research Council (Canada), the Ministry of Science and Technology (MOST; Taiwan), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA; Taiwan) and Korea Astronomy and Space Science Institute (KASI; Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, the Associated Universities, Inc./National Radio Astronomy Observatory (AUI/NRAO) and the National Astronomical Observatory of Japan (NAOJ). APEX, a collaboration between the Max Planck Institute for Radio Astronomy (Germany), the Onsala Space Observatory (Sweden) and ESO, is operated by ESO. The 30-meter telescope is operated by IRAM (the IRAM partner organizations are MPG (Germany), CNRS (France) and IGN (Spain)). The JCMT is operated by the East Asian Observatory on behalf of the Center for Astronomical Mega-Science of the Chinese Academy of Sciences, NAOJ, ASIAA, KASI, the National Astronomical Research Institute of Thailand and organizations in the United Kingdom and Canada. The LMT is operated by INAOE and UMass, the SMA is operated by Center for Astrophysics | Harvard & Smithsonian and ASIAA, and the UArizona SMT is operated by the University of Arizona. The SPT is operated by the University of Chicago with specialized EHT instrumentation provided by the University of Arizona.

The Greenland Telescope (GLT) is operated by ASIAA and the Smithsonian Astrophysical Observatory (SAO). The GLT is part of the ALMA-Taiwan project, and is supported in part by the Academia Sinica (AS) and MOST. NOEMA is operated by IRAM and the UArizona 12-meter telescope at Kitt Peak is operated by the University of Arizona.

[2] Black holes are the only objects we know of where mass scales with size. A black hole a thousand times smaller than another is also a thousand times less massive.

Publications:
First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way: 10.3847/2041-8213/ac6674 and https://iopscience.iop.org/article/10.3847/2041-8213/ac6674
All 10 publications in Astrophysical Journal Letters:
https://iopscience.iop.org/journal/2041-8205/page/Focus_on_First_Sgr_A_Results

Pictures for Download:
https://www.uni-frankfurt.de/119021712

1) EHT_PR_Main_Image_Original.tiff
First image of the black hole at the centre of the Milky Way
This is the first image of Sagittarius A* (Sgr A*), the supermassive black hole at the centre of our galaxy, captured by the Event Horizon Telescope (EHT). It is the first direct visual evidence of the presence of this black hole. The telescope is named after the “event horizon", the boundary of the black hole beyond which no light can escape.
Although we cannot see the event horizon itself, because it cannot emit light, glowing gas orbiting around the black hole reveals a tell-tale signature: a dark central region (called a “shadow") surrounded by a bright ring-like structure. The new view captures light bent by the powerful gravity of the black hole, which is four million times more massive than our Sun. The image of the Sgr A* black hole is an average of the different images the EHT Collaboration has extracted from its 2017 observations.
Image credit: EHT Collaboration

2) Simulation_AccretionDisk_SgrAStar.png
Simulation of the Accretion Disk around the Black Hole Sgr A*
Example of a simulation of how the gas orbits the black hole in the center of our Milky Way and emits radio waves at 1.3 mm. Credit: Younsi, Fromm, Mizuno & Rezzolla (University College London, Goethe University Frankfurt)

3) EHT_PR_Secondary_Image.tiff
Making of the image of the black hole at the centre of the Milky Way (image)
The Event Horizon Telescope (EHT) Collaboration has created a single image (top frame) of the supermassive black hole at the centre of our galaxy, called Sagittarius A* (or Sgr A* for short), by combining images extracted from the EHT observations. The main image was produced by averaging together thousands of images created using different computational methods — all of which accurately fit the EHT data. This averaged image retains features more commonly seen in the varied images and suppresses features that appear infrequently.
The images can also be clustered into four groups based on similar features. An averaged, representative image for each of the four clusters is shown in the bottom row. Three of the clusters show a ring structure, but with differently distributed brightness around the ring. The fourth cluster contains images that also fit the data but do not appear ring-like.
The bar graphs show the relative number of images belonging to each cluster. Thousands of images fell into each of the first three clusters, while the fourth and smallest cluster contains only hundreds of images. The heights of the bars indicate the relative “weights", or contributions, of each cluster to the averaged image at top.
Image credit: EHT Collaboration

4) Rezzolla_Luciano_2019_Credit_JuergenLecher.jpg
Luciano Rezzolla
Luciano Rezzolla, Professor für Theoretische Astrophysik, Goethe-Universität Frankfurt. Credit: Juergen Lecher for Goethe University Frankfurt

Youtube-Playlist Black Hole
Find further animations on how the picture of the black hole in the center of our galaxy was made on the Goethe
University's playlist „Black Hole“
https://youtube.com/playlist?list=PLn5gYfEKIag8nps1GKLqUW35AOgQY7aM2

Further pictures and video clips provided by EHT Collaboration:
https://eventhorizontelescope.teamwork.com/#notebooks/240600 (Animationen)
https://eventhorizontelescope.teamwork.com/#notebooks/240540 (Bilder)

Websites
https://eventhorizontelescope.org/  EHT Website
https://blackholecam.org/ Black Hole Cam-Project

Contact:
Professor Luciano Rezzolla
Institute for Theoretical Physics
Goethe University Frankfurt, Germany
Phone: +49 (69) 798-47871
rezzolla@itp.uni-frankfurt.de
https://astro.uni-frankfurt.de/rezzolla/

When Mongolian gazelles gather on green pastureland, 100,000 animals can soon come together. Then they scatter to the four winds. Why that is and how these animals can be protected in light of Mongolia's booming economy explains animal ecologist Thomas Müller in the current edition of “Forschung Frankfurt", which has now been published in English translation. Under the title “In motion", Goethe University Science Magazine presents a multifaceted spectrum of research projects, viewpoints and analyses by Goethe University researchers.

FRANKFURT. About a million gazelles still inhabit one of the last intact grasslands in the temperate zone: the Eastern Mongolian steppe. When the lush green grass begins to sprout, huge groups of animals gather to graze – and then disappear again into the landscape's vast expanses. Professor Thomas Müller, Senckenberg Biodiversity and Climate Research Centre and Goethe University, and his team have studied the animals' seemingly chaotic migratory behaviour, which is unique worldwide, for many years. Time is pressing, as economic development in Mongolia is on collision course with these wild animals: roads, railway lines and oil production facilities are forcing their way deeper and deeper into the steppe. New nature conservation concepts need to be developed here, as even the large protection zones created by Mongolia in the past years do not meet the animals' need for space: Müller estimates that a gazelle can explore an area the size of Hungary during its lifetime.

In other articles in the current issue of “Forschung Frankfurt", scientists from Goethe University report on their research projects related to various aspects of motion, for example how they teach computers to recognise different movements such as “cutting" or “waving", how ADHD can affect adults too or how two movements in quantum physics are superimposed, each of which only occurs with a certain probability. Other articles explore, for example, how smartphones, which are almost ubiquitous, are changing film as a medium or how sports clubs can foster the integration of immigrants.

Journalists can order the current English-language issue of Forschung Frankfurt (2/2021) free of charge from: ott@pvw.uni-frankfurt.de

All articles are available online at www.forschung-frankfurt.de (then go to EN) or https://tinygu.de/ENForschungFrankfurt

Contrary to a concept propagated for almost 30 years, specialized pro-resolving lipid mediators, which our body forms from polyunsaturated omega-3 fatty acids, evidently do not actively stop inflammation. Although such resolvins or lipoxins can be produced under laboratory conditions, it is highly probably that they play no physiological role whatsoever. This is corroborated by a review undertaken by an international research team led by Professor Dieter Steinhilber from Goethe University, Frankfurt. The starting point for this work, which has caused quite a stir in the academic community, was experimental findings by the Research Training Group “Resolution of inflammation – Mediators, signalling and therapeutic options" at Goethe University.

FRANKFURT. Inflammation is the result of an active defence reaction by our immune system. It mostly disappears by itself. It was once assumed to be a passive process because the immune cells involved, having done their work, gradually die off or migrate. Today, we know that our body also actively controls the resolution of inflammation. To this end, certain cells of the innate immune system, known as M1 macrophages, which are pro-inflammatory and in the first instance serve as a defence mechanism, transform into M2 macrophages, which are anti-inflammatory and primarily help to heal wounds.

In the past, the formation of specialized pro-resolving lipid mediators (SPMs) was considered an important molecular effect of this transformation. Since their discovery in 1984, they have given an ever-growing group of “resolutionists" worldwide reason to hope that it would one day be possible to intervene therapeutically in inflammatory processes by means of synthetic “inflammation resolvers" (resolvins).

The drugs against inflammation and its symptoms that are currently available – such as acetylsalicylic acid and COX-2 inhibitors – act, by contrast, as antagonists to certain arachidonic acid metabolism reactions, which generate pro-inflammatory tissue hormones. These include thromboxane and prostaglandins on the one hand and leukotrienes on the other. Only two metabolism steps away from arachidonic acid, those SPMs are also produced to which an anti-inflammatory effect has so far been attributed.

Indeed, a doctoral thesis in the Research Training Group “Resolution of inflammation – Mediators, signalling and therapeutic options" established at Goethe University in 2017 showed that the anti-inflammatory macrophages form the two enzymes needed to produce SPMs. However, only under non-physiological conditions – the researchers added stimulators that increased the calcium permeability of the macrophage membrane (ionophores) – could tiny amounts of SPMs be detected. Even when, as another study demonstrated, pre-treated substrates of these enzymes were added to cell cultures of certain white blood cells (neutrophilic leukocytes), these substrates were hardly converted to lipoxins and resolvins.

Further suspicion was triggered by earlier work on SPM receptors by Professor Stefan Offermanns, who, like Professor Dieter Steinhilber, is project leader in the Collaborative Research Centre “Signalling by fatty acid derivatives and sphingolipids in health and disease" hosted by Goethe University. In his study, no effect of lipoxin A via the corresponding G protein-coupled receptor could be identified. Lipid mediators transmit their signals via these receptors. Moreover, in the blood plasma of healthy volunteers, SPMs could at best be found in the single-digit picogramme range, even when using the most sensitive and selective methods (coupling of chromatography and mass spectrometry).

On the basis of these findings, Steinhilber's research team combed through all the papers on SPMs published so far. This review endorsed their dismantling of the SPM concept: human leukocytes, to which macrophages also belong, can at best synthesize small amounts of SPMs. These amounts are so tiny that they cannot be reliably quantified even with state-of-the-art analytics. There is no correlation between SPM synthesis and the resolution of an inflammatory reaction nor with a targeted intake of polyunsaturated omega-3 fatty acids. To date, there is no valid evidence of functional SPM receptors.

“Insiders have known for a long time that the SPM concept was questionable," says Steinhilber. “But until now no one has taken the trouble to gather all the doubts together." There had to be another mechanism of active inflammation resolution, he says. “Because the transformation of pro-inflammatory M1 macrophages into anti-inflammatory M2 macrophages clearly goes hand in hand with a change in the lipid and cytokine profile."

“The search for the molecular signals that our body uses to actively prevent excessive or chronic inflammation continues to be exciting," says Professor Bernhard Brüne, Vice President of Goethe University and spokesperson for the Research Training Group. “It's a source of motivation for our future research."

Publication: Nils Helge Schebb, Hartmut Kühn, Astrid S. Kahnt, Katharina M. Rund, Valerie B. O'Donnell, Nicolas Flamand, Marc Peters-Golden, Per-Johan Jakobsson, Karsten H. Weylandt, Nadine Rohwer, Robert C. Murphy, Gerd Geisslinger, Garret A. FitzGerald, Julien Hanson, Claes Dahlgren, Mohamad Wessam Alnouri, Stefan Offermanns, Dieter Steinhilber: Formation, Signalling and Occurrence of Specialized Pro-Resolving Lipid Mediators – What is the Evidence so far? Frontiers in Pharmacology (2022) https://doi.org/10.3389/fphar.2022.838782

Further information:
Professor Dieter Steinhilber
Institute of Pharmaceutical Chemistry
Goethe University Frankfurt, Germany
Tel.: +49 (0)69 798-29324
Steinhilber@em.uni-frankfurt.de
https://www.uni-frankfurt.de/53483647/Arbeitskreis_Prof__Dr__Steinhilber

A clinical study from Spain recently confirmed laboratory experiments made by researchers of Goethe University Frankfurt and University of Kent who showed that the protease inhibitor aprotinin prevented cells to be infected by SARS-CoV2. The authors of the clinical study report that patients receiving an aprotinin aerosol could be discharged from hospital significantly earlier.

FRANKFURT. SARS-CoV-2, the coronavirus that causes COVID-19, needs its spike proteins to dock onto proteins (ACE receptors) on the surface of the host cells. Before this docking is possible, parts of the spike protein have to be cleaved by host cell's enzymes called proteases. In 2020, a scientific team led by Professor Jindrich Cinatl (Goethe University Frankfurt, Germany), Professor Martin Michaelis and Professor Mark Wass (both University of Kent, UK), conducted cell culture experiments and found that aprotinin, a protease inhibitor, could inhibit virus replications by preventing SARS-CoV-2 entry into host cells.

In a more recent study, the research consortium further showed that aprotinin is also effective against the Delta and Omicron variants.

Now, a Spanish research consortium has published the findings of a phase III clinical study investigating the use of an aprotinin aerosol in COVID-19 patients. Among other improvements, aprotinin treatment reduced the length of hospital stays by five days.

Professor Jindrich Cinatl, Goethe University Frankfurt, said: “This shows how scientific collaborations work even without a direct relationship between researchers. I am very glad that our cell culture study inspired this successful clinical trial".

Professor Martin Michaelis, University of Kent, said: “Our cell culture data looked very convincing. It is exciting that aprotinin has now also been shown to be effective against COVID-19 in patients."

Spanish study: Francisco Javier Redondo-Calvo et. al.: Aprotinin treatment against SARS-CoV-2: A randomized phase III study to evaluate the safety and efficacy of a pan-protease inhibitor for moderate COVID-19. Eur. J. Clin. Invest. (2022) https://doi.org/10.1111/eci.13776

More about the studies of Goethe University and University of Kent:
1) The drug aprotinin inhibits entry of SARS-CoV2 in host cells https://aktuelles.uni-frankfurt.de/englisch/the-drug-aprotinin-inhibits-entry-of-sars-cov2-in-host-cells/

2) Researchers of the University of Kent and Goethe-University find explanation why the Omicron variant causes less severe disease https://aktuelles.uni-frankfurt.de/englisch/researchers-of-the-university-of-kent-and-goethe-university-find-explanation-why-the-omicron-variant-causes-less-severe-disease/

Further Information:
Professor Jindrich Cinatl
Institute of Medical Virology
University Hospital Frankfurt and Goethe University Frankfurt
Phone.: +49 (0) 69 6301-6409
cinatl@em.uni-frankfurt.de