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From optical R-band data of the double quasar QSO 0957+561A,B, we made two new difference light curves (with an overlap of about 330d between the time-shifted light curve for the A image and the magnitude-shifted light curve for the B image). We observed noisy behaviours around the zero line and no short time-scale events (with a duration of months), where the term `event' refers to a prominent feature that may be a result of microlensing or another source of variability. Only one event lasting two weeks and rising -33mmag was found. Measured constraints on the possible microlensing variability can be used to obtain information on the granularity of the dark matter in the main lensing galaxy and the size of the source. In addition, one can also test the ability of the observational noise to cause the rms averages and the local features of the difference signals. We focused on this last issue. The combined photometries were related to a process consisting of an intrinsic signal plus a Gaussian observational noise. The intrinsic signal has been assumed to be either a smooth function (polynomial), a smooth function plus a stationary noise process, or a correlated stationary process. Using these three pictures without microlensing, we derived some models totally consistent with the observations. We finally discussed the sensitivity of our telescope (at Teide Observatory) to several classes of microlensing variability.
We present CHANDRA observations of the X-ray luminous, distant galaxy cluster RBS797 at z=0.35. In the central region the X-ray emission shows two pronounced X-ray minima, which are located opposite to each other with respect to the cluster centre. These depressions suggest an interaction between the central radio galaxy and the intra-cluster medium, which would be the first detection in such a distant cluster. The minima are symmetric relative to the cluster centre and very deep compared to similar features found in a few other nearby clusters. A spectral and morphological analysis of the overall cluster emission shows that RBS797 is a hot cluster (T=7.7+1.2-1.0 keV) with a total mass of Mtot(r500)= 6.5+1.6-1.2 *E14Msun.
Spectral lines formed in stellar winds from OB stars are observed to exhibit profile variations. Discrete Absorption Components (DACs) show a remarkably slow wavelength drift with time. In a straightforward interpretation, this is in sharp contradiction to the steep velocity law predicted by the radiation-driven wind theory, and by semi- empirical profile fitting. In the present paper we re-discuss the interpretation of the drift rate. We show that the Co- rotating Interaction Region (CIR) model for the formation of DACs does not explain their slow drift rate as a consequence of rotation. On the contrary, the apparent acceleration of a spectral CIR feature is even higher than for the corresponding kinematical model without rotation. However, the observations can be understood by distinguishing between the velocity field of the matter flow, and the velocity law for the motion of the patterns in which the DAC features are formed. If the latter propagate upstream against the matter flow, the resulting wavelength drift mimics a much slower acceleration although the matter is moving fast. Additional to the DACs, a second type of recurrent structures is present in observed OB star spectra, the so-called modulations. In contrast to the DACs, these structures show a steep acceleration compatible with the theoretically predicted velocity law. We see only two possible consistent scenarios. Either, the wind is accelerated fast, and the modulations are formed in advected structures, while the DACs come from structures which are propagating upstream. Or, alternatively, steep and shallow velocity laws may co-exist at the same time in different spatial regions or directions of the wind.
Rumänien vor den Toren der Europäischen Union : Migration, Landwirtschaft und ländlicher Raum
(2001)
In order to broaden our understanding of the eukaryotic CO2- concentrating mechanism the occurrence and localization of a thylakoid-asssocaate carbonic anhydrase (EC 4.2.1.1) were studied in the green algae Tetraedron on minimum and Chlamydomonas noctigama. Both algae induce a CO2-concentrating mechanism when grown under limiting CO2 conditions. Using mass- spectrometric measurements of O-18 exchange from doubly labelled CO2, the presence of a thylakoid-associated carbonic anhydrase was confirmed for both species. From purified thylakoid membranes, photosystem I (PSI), photosystem II (PSII) and the light-harvesting complex of the photosynthetic apparatus were isolated by mild detergent gel. The protein fractions were identified by 77 K fluorescence spectroscopy and immunological studies. A polypeptide was found to immunoreact with an antibody raised against thylakoid carbonic anhydrase (CAH3) from Chlamydomonas reinhardtii. It was found that this polypeptide was mainly associated with PSII, although a certain proportion was also connected to light harvesting complex II. This was confirmed by activity measurements of carbonic anhydrase in isolated bands extracted from the mild detergent gel. The thylakoid carbonic anhydrase isolated from T. minimum had an isoelectric point between 5.4 and 4.8. Together the results are consistent with the hypothesis that thylakoid carbonic anhydrase resides within the lumen where it is associated with the PSII complex.
Thematic cartography
(2001)
Im Handbuchartikel wird eine kurze Übersicht über das Schicksal der Juden seit der Ersten Tschechoslowakischen Republik (1918-1938) bis in die heutige Zeit gegeben. Behandelt werden folgende Fragestellungen: Der rechtliche Status der Juden nach der Verfassung und dem Sprachengesetz von 1920. Die soziale, berufliche und nationale Gliederung des tschechoslowakischen Judentums. Die Lage der Juden im Protektorat Böhmen und Mähren. Das Ghetto Theresienstadt. Nach 1945.
Im vorliegenden Beitrag untersucht Verfasser die Position des niedersorbischen und obersorbischen finiten Verbs im einfachen und komplexen Satz. Entgegen der bisher vertretenen Auffassung, dass das Sorbische eine SOV Sprache sei, wird gezeigt, dass im einfachen Satz mit einem finiten Verb das Os. und Ns. die Verbletzt-Stellung aufweisen, während das Deutsche die obligatorische V2-Position zeigt. Im einfachen Satz mit zusammengesetztem Prädikat (z.B. in temporalen und modalen periphrastischen/analytischen Konstruktionen) muss im Ns. das verbale Auxiliar als Klitik an V2-Position (Wackernagel-Position, möglicherweise Comp) rücken und das Vollverb verbleibt in der VP in situ , während im Os. die Befundlage nicht so eindeutig ist. Die Analyse erfolgt mit Beispielen aus den gesprochenen Dialekten der os. und ns. Sprachen. Der bisher rigoros behauptete und durch Sprachkontakt ausgelöste Einfluss des Deutschen wird zumindest in Bezug auf das Ns. einer Überprüfung unterzogen und relativiert.
Energie
(2001)