7 results on '"de Vera, Jean-Pierre"'
Search Results
2. Die Verbindung zwischen Polarforschung und Weltraumforschung
- Author
-
de Vera, Jean Pierre Paul
- Subjects
Weltraumforschung ,Eismonde ,Polarforschung ,Mars - Published
- 2014
3. Emissivity Spectra of Meteoritic Powders mixed with Liquid Formamide (CH3NO) at Different Temperatures
- Author
-
Saladino, Raffaele, Maturilli, Alessandro, Helbert, Jörn, de Vera, Jean Pierre Paul, D'Amore, Mario, and Ferrari, Sabrina
- Subjects
Astoroiden ,Experimentelle Planetenphysik ,Formamide - Abstract
We set-up an experiment at the Planetary Emissivity Laboratory (PEL) to investigate a key aspect in the prebiotic chemistry of formamide: the surface reactivity of minerals used as catalysts. The interaction of formamide and the reaction products on mineral surface, as well as, the sequestration processes in the mineral pores, can facilitate the concentration of products allowing for possible polymerization. Three meteorites, NWA2828 (PEL ID 00000887), Al Haggounia (PEL ID 00000888), and Dhofar959 (PEL ID 00000889), were used in this experiment. All the samples were reduced in the grain size fraction < 125 µm and stored in a desiccator before measuring. Each sample was poured in one from a set of identical stainless steel cups, having 5 mm thick bottom, internal diameter 50 mm, rim thickness 2 mm, and 20 mm total height. Emissivity of the samples was measured by means of a Bruker Vertex 80V coupled to an emissivity chamber (equipped with a rotating carousel to measure several samples without breaking the vacuum), both evacuable to < 1 mbar. The dry samples were placed in the emissivity chamber, each of them having a temperature sensor in contact with the surface of the sample, reading the effective temperature of the emitting skin. The “dry” meteorites were measured in vacuum (0.8 mbar) at 70° C on the sample surface, successively liquid formamide was vaporized on the samples surface, the cup was immediately transferred in the emissivity chamber, and evacuated. Each sample was measured at 70°, 100°, 140°, and 200° C. Then each cup was cooled in vacuum and put back in the desiccator. For each sample after this thermal processing, a small amount of heated material was used to fill a cup for reflectance measurements. Since cold reflectance measurements cannot be compared with hot emissivity, those measurements have been taken to better understand the processes happening in the moisturized soil after heating. For all of the samples, when heating at 70°C we noticed in the emissivity spectra strong signatures attributable to liquid formamide. We interpret them as being originated from a column of hot vaporized formamide, lying above the sample surface. For all the samples this effect vanished already at 100°C, probably due to complete evaporation of liquid formamide that was deposited on the meteorite sample surfaces. However, all the spectra measured at 100° and 140° C show signs of the presence of formamide, that we infer from comparing them with the 70° C dry measurement of the same sample. For 2 samples out of 3, when heating at 200°C (and only there) a new feature appears at 7.08 µm. This band is very close to a similar band that liquid formamide has at 7.19 µm, and that was even present in all the spectra of wet meteorites taken at 70°C. We interpret this band shift as a possible sign of interaction of formamide with the catalyst (the meteorite powder): the CH bend responsible for that is probably strengthening.
- Published
- 2013
4. Robust symbiotic microbial communities in space research
- Author
-
Kukharenko, O., Podolich, O., Rybitska, A., Reshetnyak, G., Burlak, L., Ovcharenko, L., Voznyuk, T., Moshynets, O., Rogutskyi, I., Zaets, I., Yaneva, O., Reva, O., Pidgorskiy, V., Rabbow, Elke, de Vera, Jean Pierre Paul, Yatsenko, V., Kozyrovska, N., and Fedorov, O
- Subjects
Strahlenbiologie ,Planetenphysik ,probiotics ,extraterrestrial manned bases ,space research ,manned space missions - Abstract
Naturally occurring symbiotic microbial communities (SMK) are the most robust assemblages for a multipurpose use in keeping humans healthy and soil fertile. Especially, safe and reliable SMK are needed for producing probiotics and ferments valuable for health problems prophylaxis. This is true for long-term expeditions, outposts, extraterrestrial permanently-manned bases where humans are exposed to adverse environmental factors, weakening the immune system. The kombucha beverage has been used in human society within millennia as a probiotic drink which is produced by naturally occurring mixed populations of living microorganisms. Here, we discuss the potential of the kombucha culture for outposts in far future missions.
- Published
- 2012
5. Recent Mars: A Habitable Planet? – Results from Investigations in Space, in Mars Analogue Habitats and from Laboratory and Theoretical Studies
- Author
-
de Vera, Jean Pierre Paul, Hauber, E., Jänchen, J., Koncz, Alexander, Lorek, Andreas, Möhlmann, D., and Spohn, Tilman
- Subjects
habitability ,Planetenphysik ,Mars ,extant life ,field studies - Abstract
Mars is a frozen desert planet. Considerable intense UV radiation fluxes reach its surface and with its thin and 95 % CO2 rich atmosphere and an atmospheric pressure of approximately 6 mbar this planet is not supposed to be habitable. But according to a variety of different experiments during the last decade where microorganisms were investigated under Mars-like environmental conditions there is evidence that even recent Mars appears to be a habitable planet. The habitability of the surface and upper subsurface of Mars depends on one hand on the viability and adaptation capacity of microorganisms under Mars-like environments and on the other hand on the planet's energy resources and liquid water availability. Besides chemical, inorganic energy sources in the soil intense solar radiation is available as additional energy source on the surface of Mars but might be harmful for most of known terrestrial life forms. However, previous studies on extremophilic microorganisms which were performed on space exposure platforms (e.g. BIOPAN on the satellite FOTON and EXPOSE on ISS) show the high resistance of tested bacteria, archaea and lichens to space radiation and desiccation caused by vacuum. During Mars simulation experiments photosynthesizing microorganisms are even able to do photosynthesis periodically. The periodicity of the photosynthetic activity depends on the diurnal cycle with its varying temperatures and relative humidity. It is important to emphasize that the aforementioned space resistant microorganisms are mainly collected in polar and alpine habitats. They are living in permafrost regions with high UV radiation income and extreme dryness provoking high adaptation strategies. Because of these environmental parameters the alpine, desert and polar habitats were characterized as Mars analogue. The Mars analogy of these regions can also be justified by comparing the colonized alpine and polar field profiles with surface structures on Mars. Numerous investigations were done during field campaigns in the Alps, the Arctic (Svalbard) and in Antarctica. Based on these field investigations it becomes obvious that gullies, polygon rich regions and micro caves, fissures and cracks in rocks can be seen as suitable candidates for habitable areas on the surface of Mars in addition to the supposed ice rich environment in the subsurface. As mentioned above, the habitability of Mars depends also on the availability of liquid water. Due to the presence of salts and perchlorate rich soils on Mars water can for sufficient relative humidity remain in a liquid phase, forming at least temporary liquid cryobrines far below the freezing point, which e.g. might be useful for some halophilic microorganisms. This may be in favour of the habitability of the Martian surface. In addition the habitability can also be influenced by the sorption and desorption capacity of other soil particles. These particles and salty solutions could avoid or enhance the liquid phase of water. Processes enhancing the liquefaction of water might explain the recently observed rheological events provoking e.g. the formation of gullies on the surface of Mars which are known as real habitats for a diversity of microorganisms on terrestrial martian analogue environments mostly present in the polar regions. All presently enumerated factors are positively emphasizing that habitability of recent Mars is particularly probable for some of terrestrial life forms.
- Published
- 2011
6. Recent Mars: a habitable planet?
- Author
-
de Vera, Jean Pierre Paul, Lorek, Andreas, and Koncz, A.
- Subjects
habitability ,alga ,Planetenphysik ,Antarctica ,Mars ,micro-niches ,lichens ,cyanobacteria - Abstract
The GANOVEX X expedition (German Antarcic North Victoria Land Expedition) in the Antarctic summer season 2009/2010 took place on the Antarctic continent. Besides analysis on the geological formations, the distribution of microorganisms as lichens, fungi, green alga and cyanobacteria has been studied along a longitudinal and altitude transect. A diversity of micro-niches has been discovered. Cosmopolites and endemic microorganisms developed adaptation strategies to colonize retreat areas of eroded surfaces, fissures and cracks of granite, volcanic and metamorphic rocks in permafrost regions. These specific habitats were additionally characterized by measurements of the macro- and microclimate (UV-, IR-, VIS-/PAR- radiation, humidity, temperature, atmospheric ozone, water and aerosol content). Based on the discoveries in the mentioned area of the Transantarctic Mountains and due to comparisons to previous results obtained from some of the space-exposed cosmopolites in the space experiments “Lithopanspermia” on BIOPAN 6 / FOTON M3 satellite and “LIFE” on EXPOSE on the International Space Station (ISS) as well as from Mars simulations at the HUMILAB (DLR Berlin), we conclude, that these investigated microorganisms from the Antarctic transect as well as from Spitsbergen and from alpine regions can be characterized as resistant to Mars conditions and that the recent Mars is probably still a habitable planet for Arctic, Antarctic and alpine microorganisms.
- Published
- 2011
7. Grenzen des Überlebens: Flechten als Modellsystem für das Potential von Adaptationsmechanismen eines Symbioseorganismus unter Extrembedingungen
- Author
-
de Vera, Jean-Pierre Paul
- Subjects
Anpassung an Extrembedingungen ,Extraterrestrik ,Flechten ,UV-Strahlung - Published
- 2006
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.