A research group lead by scientists at the Goethe University Frankfurt discover details on how clouds form
FRANKFURT. New insights into cloud formation were obtained by scientists from the Goethe University of Frankfurt in an international collaboration. They found out that amines could play an important role in aerosol formation. They act as a kind of “superglue”. Aerosol particles influence the climate through their role in cloud formation because clouds can only form if so-called cloud condensation nuclei (CCN) are available.
It has been known for several years that sulfuric acid contributes to the formation of tiny aerosol particles, which play an important role in the formation of clouds. The new study by Kürten et al. shows that dimethylamine can tremendously enhance new particle formation. The formation of neutral (i.e. uncharged) nucleating clusters of sulfuric acid and dimethylamine was observed for the first time.
Previously, it was only possible to detect neutral clusters containing up to two sulfuric acid molecules. However, in the present study molecular clusters containing up to 14 sulfuric acid and 16 dimethylamine molecules were detected and their growth by attachment of individual molecules was observed in real-time starting from just one molecule. Moreover, these measurements were made at concentrations of sulfuric acid and dimethylamine corresponding to atmospheric levels (less than 1 molecule of sulfuric acid per 1 x 1013 molecules of air).
The capability of sulfuric acid molecules together with water and ammonia to form clusters and particles has been recognized for several years. However, clusters which form in this manner can vaporize under the conditions which exist in the atmosphere. In contrast, the system of sulfuric acid and dimethylamine forms particles much more efficiently because even the smallest clusters are essentially stable against evaporation. In this respect dimethylamine can act as “superglue” because when interacting with sulfuric acid every collision between a cluster and a sulfuric acid molecule bonds them together irreversibly. Sulphuric acid as well as amines in the present day atmosphere have mainly anthropogenic sources. Sulphuric acid is derived mainly from the oxidation of sulphur dioxide while amines stem, for example, from animal husbandry. The method used to measure the neutral clusters utilizes a combination of a mass spectrometer and a chemical ionization source, which was developed by the University of Frankfurt and the University of Helsinki. The measurements were made by an international collaboration at the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN (European Organization for Nuclear Research).
The results allow for very detailed insight into a chemical system which could be relevant for atmospheric particle formation. Aerosol particles influence the Earth’s climate through cloud formation: Clouds can only form if so-called cloud condensation nuclei (CCN) are present, which act as seeds for condensing water molecules. Globally about half the CCN originate from a secondary process which involves the formation of small clusters and particles in the very first step followed by growth to sizes of at least 50 nanometers. The observed process of particle formation from sulfuric acid and dimethylamine could also be relevant for the formation of CCN. A high concentration of CCN generally leads to the formation of clouds with a high concentration of small droplets; whereas fewer CCN lead to clouds with few large droplets. Earth’s radiation budget, climate as well as precipitation patterns can be influenced in this manner. The deployed method will also open a new window for future measurements of particle formation in other chemical systems.
Kürten, A., Jokinen, T., Simon, M., Sipilä, M., Sarnela, N., Junninen, H., Adamov, A., Almeida, J., Amorim, A., Bianchi, F., Breitenlechner, M., Dommen, J., Donahue, N. M., Duplissy, J., Ehrhart, S., Flagan, R. C., Franchin, A., Hakala, J., Hansel, A., Heinritzi, M., Hutterli, M., Kangasluoma, J., Kirkby, J., Laaksonen, A., Lehtipalo, K., Leiminger, M., Makhmutov, V., Mathot, S., Onnela, A., Petäjä, T., Praplan, A. P., Riccobono, F., Rissanen, M. P., Rondo, L., Schobesberger, S., Seinfeld, J. H., Steiner, G., Tomé, A., Tröstl, J., Winkler, P. M., Williamson, C., Wimmer, D., Ye, P., Baltensperger, U., Carslaw, K. S., Kulmala, M., Worsnop, D. R., and Curtius, J.: Neutral molecular cluster formation of sulfuric acid-dimethylamine observed in real-time under atmospheric conditions, Proc. Natl. Acad. Sci. USA, doi/10.1073/pnas.1404853111, 2014.
Contact: Dr. Andreas Kürten, Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt am Main, Telefon 0049 (69) 798-40256, E-Mail: firstname.lastname@example.org
Soil bacteria contribute to the taste and smell
FRANKFURT. Truffles, along with caviar, are among the most expensive foods in the world. Because they grow underground, people use trained dogs or pigs to find them. But the distinctive smell of truffles is not only of interest to gourmets. A group of German and French scientists under the direction of the Goethe University Frankfurt have discovered that the smell of white truffles is largely produced by soil bacteria which are trapped inside truffle fruiting bodies.
White truffles from the Piedmont region in Italy can reach 5,000 Euro per kilogram, and black truffles from the Périgord region in Southern France as much as 2,000 Euro per kilogram. Particularly large specimens even fetch prices of up to 50,000 Euro per kilogram at auctions. Connoisseurs search for the precious delicacies near hazelnut trees, oaks and some species of pine. This is because truffles grow in a symbiotic relationship with the trees. For scientists truffles are therefore a model organism to investigate how symbiosis evolved between plants and fungi.
Truffles are also useful to study fungal smell and flavour. Understanding how flavours are created is indeed very important to the food industry. Yeasts and bacteria which make cheese and wine have been researched in depth, but little is known about how the flavour of other organisms, including truffles, is created.
Over the past 10 years, researchers already suspected that micro-organisms trapped inside truffle fruiting bodies contributed to the flavour. "When the genome of the black Perigord truffle was mapped in 2010, we thought that the fungus had sufficient genes to create its flavour on its own", junior professor Richard Splivallo from the Institute for Molecular Life Sciences at the Goethe University explained.
The team made up of German and French scientists studied the white truffle Tuber borchii. It is native to Europe but has been recently introduced in New Zealand and Argentina. The researchers were able to show that bacteria produce a specific class of volatile cyclic sulphur compounds, which make up part of the distinctive truffle smell. Dogs and pigs are able to find truffles underground thanks to the slightly sulphuric smell.
"However, our results cannot be transferred to other types of truffles", Splivallo says, "because the compounds we investigated are only found in the white truffle Tuber borchii." For this reason, in the future they plan to study compounds which are found in the Périgord and Piermont truffles and are common to all types of truffles. "We don't just want to know which part of the truffle flavour is produced by bacteria. We are also interested in how the symbiosis between fungi and microorganisms has evolved and how this benefits both symbiotic partners."
Splivallo R, Deveau A, Valdez N, Kirchhoff N, Frey-Klett P, Karlovsky P. (2014). Bacteria associated with truffle-fruiting bodies contribute to truffle aroma. Environmental Microbiology. DOI: 10.1111/1462-2920.12521
Information: Junior-Prof. Richard Splivallo, Institute for Molecular Bio Sciences, Campus Riedberg, Tel.: 0049(0)69/ 798- 42193, Splivallo@bio.uni-frankfurt.de.
Long lost Roman fort discovered
FRANKFURT. In the course of an educational dig in Gernsheim in the Hessian Ried, archaeologists from Frankfurt University have discovered a long lost Roman fort: A troop unit made up out of approximately 500 soldiers (known as a cohort) was stationed there between 70/80 and 110/120 AD. Over the past weeks, the archaeologists found two V-shaped ditches, typical of this type of fort, and the post holes of a wooden defensive tower as well as other evidence from the time after the fort was abandoned.
An unusually large number of finds were made. This is because the Roman troops dismantled the fort and filled in the ditches when they left. In the process they disposed of a lot of waste, especially in the inner ditch. "A bonanza for us," according to Prof. Dr. Hans-Markus von Kaenel from the Goethe University Institute of Archaeology. "We filled box after box with shards of fine, coarse and transport ceramics; dating them will allow us to determine when the fort was abandoned with greater accuracy than was possible before".
Up until now, little was known about Roman Gernsheim, even though findings from the Roman era have been cropping up here since the 19th century. "Previously, the only thing that seemed certain based on the finds was that an important village-like settlement, or "vicus", must have been located here from the 1st to the 3rd century, comparable with similar villages which have already been shown to have existed in Groß-Gerau, Dieburg or Ladenburg", explained dig leader Dr. Thomas Maurer. He has been travelling from Frankfurt to South Hessia for years and has published his findings in a large publication about the North Hessian Ried during Roman imperial times.
"It was assumed", continued Maurer, "that this settlement had to have been based on a fort, since it was customary for the families of the soldiers to live outside the fort in a village-like settlement." "We really hit the jackpot with this excavation campaign", said a delighted Prof. Dr. Hans-Markus von Kaenel. "The results are a milestone in reconstructing the history of the Hessian Ried during Roman times." For almost 20 years now, von Kaenel has been studying this area with the help of his colleagues and students using surveys, digs, material processing and analyses. The results have been published in over 50 articles.
The Romans built the fort in Gernsheim in order to take control of large areas to the east of the Rhine in the seventh decade of the 1st century AD and to expand the traffic infrastructure from and to the centre of Mainz-Mogontiac. The fact that Gernsheim am Rhein was very important during Roman times is supported by its favourable location for travel: A road branches off from the Mainz – Ladenburg – Augsburg highway in the direction of the Main Limes. One can assume that a Rhine harbour existed as well, but this couldn't be verified during the course of this dig. "That was always unlikely on account of the chosen location", according to Maurer. Gernsheim continued to expand during the 20th century, and this expansion threatened to wipe out more and more of the archaeological traces. While the Roman remains were mostly still hidden under fields and gardens in the year 1900, they were gradually built over and thus lost to methodical archaeological research. The last plot of any measurable size where it might still be possible to make findings from the Roman era was an area in the south west of the city between the B44 and the River Winkelbach. But in 1971 the excavators moved in here as well. Maurer added: "At the time, a few volunteers from the Heritage Conservation Society were barely able to save a few Roman finds.
On August 4 of this year, the annual educational dig run by the Goethe University Institute of Archaeology began on one of the few remaining properties which had not been built on; a double lot at Nibelungenstraße 10-12. "According to my maps of those Gernsheim sites which could be located, we are at the far western edge of the area in which the finds are concentrated, right at the edge of the lower terrace, since the nearby River Winkelbach flows into the Rhine basin from here", explained dig leader Maurer. Isolated Roman finds were made on almost all neighbouring properties during the 1970s and 1980s. "Thus the site seemed to be a worthwhile location for a dig, which turned out to be very much the case."
Over the past five weeks, 15 students of the "Archaeology and History of the Roman Provinces" course carefully stripped away the soil, mapped and documented the finds, and recovered and packaged them by type. The work was supported by Frankfurt archaeologists from the Hessian State Office for the Preservation of Historical Monuments (Hessen ARCHÄOLOGIE, Darmstadt branch) and by the Art and History Society of Schöfferstadt Gernsheim. Some members of this society, which also operates the local museum, supported the dig team on a daily basis. The documentation and the findings from this excavation campaign form the basis for a thesis at the University, work on which will start in the winter semester.
Pictures can be downloaded from: www.muk.uni-frankfurt.de/51885456
Information: Dr. Thomas Maurer, Institute of Archaeology, West End Campus, Phone: 0177-5672114, email@example.com
The authority as to the interpretation of the Islamic faith must not be left to militant extremists
FRANKFURT. At the start of the congress 'Horizons of Islamic Theology' taking place at the Goethe University in Frankfurt, representatives of the departments for Islamic Theological Studies in Germany have published a statement on the current political developments in the Middle East They state that the authority in terms of interpreting the Islamic faith must not be left to militant extremists, who are also increasingly finding followers amongst young people in Europe, but must come from the centre of German society -- including the universities.
They express their grave concern about the brutal methods being employed by followers of Islamic State. The signatories to the statement believe the causes of such a violence-centred understanding of the religion lie in the desperate socio-political situation in the Middle East and other parts of the world.
Below is the actual wording of the statement, which has now also been signed by many more academics.
“We are deeply shocked and appalled by the current political developments in the Middle East and by the terror to which the so-called “Islamic State” (IS) is subjecting civilians and prisoners of all religions and ethnicities. The outrageous violence displayed by the followers of the IS violates all principles of humanity and civilisational norms; principles which Islam itself has shared over centuries and to which it has significantly contributed. We strongly reject and condemn interpretations of Islam that pervert this religion into an anachronistic ideology of hate and violence.
Given the increasing number of young people in Europe who are aligning themselves with the ideology of the IS and similar extremist formations, we are, as representatives of Islamic theological studies, fully aware of the responsibility and the necessity to counter such interpretations of Islam by referring to the Islamic traditions themselves. The authority, in matters of interpretation of Islam, has to be based in the societal mainstream, including the universities, and must not be ceded to extremists and violent perpetrators.
In our university work and beyond, we are committed to an interpretation of Islam that is based on the ideas of humanity and non-violence, on appreciation of pluralism and on respect towards human beings regardless of their religious and other affiliations.
The current conflicts in the Middle East and in other parts of the world clearly show how quickly violence-centered interpretations of religion can emerge under desolate sociopolitical conditions.
By contrast, in the free democratic societies of Europe we see a chance to relate to the rich intellectual and religious history of Islam in a reflective way and to engage positively with other perspectives, including the critical ones. Students of Islamic theological studies in Germany should utilize their religious resources as a means to creatively shape a common future with other members of society. Muslims are an integral part of the German society, and recognition of this fact is an important stage in this endeavour. At the same time, the past and recent Islamophobic and anti-Muslim assaults have to be recognized as obstacles along this way.
It is only through a reflective approach to the Islamic teaching and practice under conditions of freedom that the production of Islamic knowledge and norms can be disassociated from the contexts of crises and political repressions. And it is only through such an approach that Islam will be able to provide productive answers to the challenges of the global coexistence. The free proliferation of academic knowledge at the universities is an important precondition for this process.”
Prof. Dr. Bekim Agai, Director of the Institute for the Studies of the Culture and Religion of Islam, Goethe University Frankfurt am Main
Prof. Dr. Maha El-Kaisy Friemuth, Director of the Department of Islamic Religious Studies, Friedrich Alexander University Erlangen-Nürnberg
Prof. Dr. Mouhanad Khorchide, Director of the Center for Islamic Theology, University of Münster
Prof. Dr. Yasar Sarikaya, Professor for Islamic Theology and its Didactics, Justus Liebig University Gießen
Prof. Dr. Erdal Toprakyaran, Director of the Center for Islamic Theology, Eberhard Karls University Tübingen
Prof. Dr. Bülent Ucar, Director of the Institute for Islamic Theology, University Osnabrück
You can sign the statement by sending your name and your institutional affiliation to: firstname.lastname@example.org
Information: Tim Sievers, B.A., Institute for the Study of Islamic Culture and Religion, Dept. of Linguistics and Cultural Studies, Tel. +49 (0)69-798-32767; email@example.com
Melissa Vo is researching the development of scene processing/The cognitive psychologist has come from the Harvard Medical School to Frankfurt.
FRANKFURT. Anyone who has ever looked for milk in somebody else's house knows that they have to go into the kitchen, open the refrigerator and look in the compartment in the fridge door. Even little children know which objects to find where within a room. Cognitive Psychologist Melissa Vo concerns herself with the question of how this scene processing ability develops. The 33-year old professor for Cognitive Psychology was recently appointed to Goethe University from Harvard Medical School. In addition, as a grant recipient of the German Research Foundation’s Emmy Noether Program, she has established the "Scene Grammar Lab" at the Psychology Institute.
"Most people take the ease with which they orient themselves in their environment, perceive and interact with objects, for granted." says Melissa Vo. She first learnt that this is by no means the case when pursuing her dissertation at the Ludwig Maximilian University in Munich, where she worked, among others, with physicists and engineers on artificial intelligence for technical systems. "While a child can find their favourite stuffed animal under a blanket without any difficulty, this presents an almost insurmountable challenge to a robot or a computer vision algorithm," she says.
While natural scenes are complex, their structure follows certain regularities that the human brain clearly learns very early. Perception is therefore greatly impacted by the knowledge of the arrangement of objects in space. For instance, most objects lie on a horizontal plane. For this reason, if experimental subjects are shown images of floating objects, the resulting irritation is expressed in altered brain signals. "The EEG then shows responses similar to when subjects hear or read a grammatically incorrect sentence," says Vo. Similarly, she was able to determine marked deviations in gaze patterns with the help of eye-tracking systems.
These observations suggest that scene processing might rely on mechanisms similar to knowledge about grammatical structures in language or even music. Melissa Vo hopes, therefore, to develop diagnostic tools for the early recognition of children who suffer from reading and writing difficulties, for example, by testing their implicit scene processing abilities before they enter formal schooling. Moreover, her work is also significant for the development of technical assistance systems that could, for example, be intended to support the elderly at home. Together with her 3 doctoral candidates, she is currently setting up a perception laboratory in Frankfurt. The experimental subjects will not only be tested in front of computer screens, as previously, but will also have to search actively for objects and interact with them in real-world scenarios using mobile eye-tracking glasses.
The Munich born and bred researcher is the daughter of a Vietnamese father and American mother. Frankfurt is an interesting research location for her because of the many co-operation partners in town, e.g. at the Institute of Psychology, the Frankfurt Institute for Advanced Studies (FIAS), or the Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with the Max Planck Society. She has other partners at the Universities of Darmstadt, Gießen and Marburg. Vo, who has worked in the USA for the past 5 years, also has established an extensive network of contacts at American Universities, which her students can benefit from. "When I was still doing my undergraduate work, my Professor arranged a research internship for me at the Columbia University in New York City. In my opinion, the experiences from that time were extremely formative and gave me more perspective," says the researcher. Together with her American colleagues, she has also organized the international OPAM conference (on Object Perception, Attention, and Memory) to promote young scientists in the field of Cognitive Psychology.
Information: Prof. Dr. Melissa Vo, Cognitive Psychology I, Campus Westend, Tel.: (069) 798 35342, firstname.lastname@example.org.