150 research outputs found
Unequal partners : security and identity at the Polish-German border
The sovereignty of the European nation states in the realm of security politics is gradually eroding. At the same time the European integration to a large degree influences the level of direct bilateral police cooperation, since cross-border crime has come to be perceived not as only a national, but as a common problem for the European nation states. At the German-Polish border, "Europe's Rio Grande", these high expectations concerning security policy are put into practice. With Poland's EU accession, Polish and German border guards are no longer spatially separated, but jointly control travellers. Joint patrols and contact points have already existed since 1998. On the one hand, the enforced meeting of German and Polish border policemen may help dismantle mutual prejudices. On the other hand, other cleavages may appear, based on cultural, systemic and institutional factors, which hinder the development of mutual trust and reinforce the asymmetrical relationship between the Schengen member Germany and the "junior partner" Poland
Blaive, Muriel/Molden, Berthold: GrenzfĂ€lle. Ăsterreichische und tschechische Erfahrungen am Eisernen Vorhang
Characterization of aromaticity in analogues of titan's atmospheric aerosols with two-step laser desorption ionization mass spectrometry
The role of polycyclic aromatic hydrocarbons (PAH) and Nitrogen containing
PAH (PANH) as intermediates of aerosol production in the atmosphere of Titan
has been a subject of controversy for a long time. An analysis of the
atmospheric emission band observed by the Visible and Infrared Mapping
Spectrometer (VIMS) at 3.28 micrometer suggests the presence of neutral
polycyclic aromatic species in the upper atmosphere of Titan. These molecules
are seen as the counter part of negative and positive aromatics ions suspected
by the Plasma Spectrometer onboard the Cassini spacecraft, but the low
resolution of the instrument hinders any molecular speciation.
In this work we investigate the specific aromatic content of Titan's
atmospheric aerosols through laboratory simulations. We report here the
selective detection of aromatic compounds in tholins, Titan's aerosol
analogues, produced with a capacitively coupled plasma in a N2:CH4 95:5 gas
mixture. For this purpose, Two-Step Laser Desorption Ionization Time-of-Flight
Mass Spectrometry (L2DI-TOF-MS) technique is used to analyze the so produced
analogues. This analytical technique is based on the ionization of molecules by
Resonance Enhanced Multi-Photon Ionization (REMPI) using a {\lambda}=248 nm
wavelength laser which is selective for aromatic species. This allows for the
selective identification of compounds having at least one aromatic ring. Our
experiments show that tholins contain a trace amount of small PAHs with one to
three aromatic rings. Nitrogen containing PAHs (PANHs) are also detected as
constituents of tholins. Molecules relevant to astrobiology are detected as is
the case of the substituted DNA base adenine
Europa an der Oder: Die Konstruktion europÀischer Sicherheit an der deutsch-polnischen Grenze
Die deutsch-polnische Grenze ist seit Beginn der 1990er Jahre Schauplatz grenzpolizeilicher Kooperationen. Doch warum entschlieĂen sich Nationalstaaten zur Zusammenarbeit in diesem sensiblen Bereich? Und wieso soll ausgerechnet die deutsch-polnische Variante so erfolgreich sein? Vor welchen Schwierigkeiten stehen deutsche und polnische GrenzschĂŒtzer in der Zusammenarbeit, und wie begegnen sie ihren Kollegen in der Alltagspraxis? Die deutsch-polnische Grenzschutzkooperation steckt voller WidersprĂŒche. Warum sie dennoch als Erfolgsmodell fĂŒr bilaterale Zusammenarbeit gehandelt wird, ist Gegenstand dieser Studie
Europa an der Oder
Die deutsch-polnische Grenze ist seit Beginn der 1990er Jahre Schauplatz grenzpolizeilicher Kooperationen. Doch warum entschlieĂen sich Nationalstaaten zur Zusammenarbeit in diesem sensiblen Bereich? Und wieso soll ausgerechnet die deutsch-polnische Variante so erfolgreich sein? Vor welchen Schwierigkeiten stehen deutsche und polnische GrenzschĂŒtzer in der Zusammenarbeit, und wie begegnen sie ihren Kollegen in der Alltagspraxis? Die deutsch-polnische Grenzschutzkooperation steckt voller WidersprĂŒche. Warum sie dennoch als Erfolgsmodell fĂŒr bilaterale Zusammenarbeit gehandelt wird, ist Gegenstand dieser Studie
Development and characterization of a single particle laser ablation mass spectrometer (SPLAM) for organic aerosol studies
A single particle instrument was developed for real-time analysis of organic aerosol. This instrument, named Single Particle Laser Ablation Mass Spectrometry (SPLAM), samples particles using an aerodynamic lens system for which the theoretical performances were calculated. At the outlet of this system, particle detection and sizing are realized by using two continuous diode lasers operating at &lambda; = 403 nm. Polystyrene Latex (PSL), sodium chloride (NaCl) and dioctylphtalate (DOP) particles were used to characterize and calibrate optical detection of SPLAM. The optical detection limit (DL) and detection efficiency (DE) were determined using size-selected DOP particles. The DE ranges from 0.1 to 90% for 100 and 350 nm DOP particles respectively and the SPLAM instrument is able to detect and size-resolve particles as small as 110â120 nm. During optical detection, particle scattered light from the two diode lasers, is detected by two photomultipliers and the detected signals are used to trigger UV excimer laser (&lambda; = 248 nm) used for one-step laser desorption ionization (LDI) of individual aerosol particles. The formed ions are analyzed by a 1 m linear time-of-flight mass spectrometer in order to access to the chemical composition of individual particles. The TOF-MS detection limit for gaseous aromatic compounds was determined to be 0.85 Ă 10<sup>&minus;15</sup> kg (&sim;4 Ă 10<sup>3</sup> molecules). DOP particles were also used to test the overall operation of the instrument. The analysis of a secondary organic aerosol, formed in a smog chamber by the ozonolysis of indene, is presented as a first application of the instrument. Single particle mass spectra were obtained with an effective hit rate of 8%. Some of these mass spectra were found to be very different from one particle to another possibly reflecting chemical differences within the investigated indene SOA particles. Our study shows that an exhaustive statistical analysis, over hundreds of particles, and adapted reference mass spectra are further needed to understand the chemical meaning of single particle mass spectra of chemically complex submicrometer-sized organic aerosols
On the structure of involutions and symmetric spaces of dihedral groups
We initiate the study of analogues of symmetric spaces for finite groups, with the current work focusing on the family of finite dihedral groups. In particular, we investigate the structure of the automorphism group, characterize the involutions within the automorphism group, and determine the fixed-point subgroup and symmetric space of each automorphism
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