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Assigning functions to nucleolar structures 总被引:8,自引:0,他引:8
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Zusammenfassung (1) 1991 konnten erstmals 4 mit Kleinsendern ausgerüstete Weißstörche mit Hilfe der Satelliten-Telemetrie auf Teilstrecken ihres Wegzugs bis zu 46 Tage lang verfolgt werden. Die japanischen Sender betrugen nur etwa 2 % des Körpergewichts der Vögel; die Ortung erfolgte durch das ARGOS-System. Die Versuchsvögel zeigten völlig normales Zugverhalten. — (2) Drei der in Brandenburg und Sachsen-Anhalt markierten Vögel waren Ostzieher und konnten über Strecken von etwa 640–4700 km verfolgt werden, 1 Storch bis zur ägyptisch-sudanesischen Grenze. Ein Westzieher konnte rund 1400 km bis zu den Pyrenäen geortet werden. — (3) Die Vögel wanderten individuell recht verschieden. 2 zogen weitgehend kontinuierlich bis in den Sudan bzw. zu den Pyrenäen, die anderen legten längere Pausen ein. Die ermittelten Zugstrecken verliefen recht geradlinig; Richtungsänderungen erfolgten vor allem an der Donau, den Karpaten, am Mittelmeer und auf der Sinai-Halbinsel. Tagesetappen betrugen mindestens bis zu 370 km, in einem Fall in 21 Tagen durchschnittlich 224 km/Tag. Die Zuggeschwindigkeit lag in der Größenordnung von 30–90 km/h. — (4) Verbesserte Sender mit längerer Lebensdauer und mehreren Ortungen pro Tag dürften es bald ermöglichen, individuelle Wanderrouten von Weißstörchen und anderen Großvögeln praktisch lückenlos zu ermitteln. Begleitmannschaften werden zudem die Zug- und Rastökologie mit Sendern ausgerüsteter Vögel mit erfassen können. Damit dürfte der Vogelschutz auf dem Zug eine neue Dimension gewinnen.
Satellite tracking of White Storks during the autumn migratory period — a pilot study
Summary (1) In 1991 parts of the routes of White Storks migrating in autumn could be recorded for the first time by satellite tracking. Four individuals could be followed for up to 46 days. Transmitter weight accounted for only about 2 % of body mass. Locations were obtained by the ARGOS system. Migratory behaviour of the experimental birds appeared to be absolutely normal. — (2) The birds were equipped with transmitters in eastern Germany. Three of them followed the eastern migration route and could be tracked from 640 up to 4700 km, the latter reaching the borders of Egypt and Sudan. A western migrant could be followed over a distance of about 1400 km towards the Pyrenees. — (3) Migration showed considerable individual variation. Whereas in two birds migration was largely continuous towards the Sudan and the Pyrenees, respectively, the other birds rested for longer periods. The tracked migration routes were fairly straight. Marked directional shifts occurred towards the Danube valley, at the Carpathian mountains, the Mediterranean and on the Sinai. Capacity per day was at least 370 km. One bird covered 224 km/day on average during a period of 21 days. Migration speed ranged in the magnitude of 30–90 km/h. — (4) Improved transmitters with increased lifetime giving several locations per day will presumably allow to record migration routes of White Storks and other large birds more completely in the near future. Escorts should then be able to closely analyse the ecology of migration and staging of their test birds. These possibilities may give a new dimension to bird conservation measures during migration.相似文献
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The effect of high CO2-concentration on photoacoustic signals from tobacco leaves is studied by means of a recently developed pulse modulation method which provides simultaneous information on photothermal and photobaric components in the millisecond time domain. High CO2-concentrations are found to induce large gas-uptake signals. Simultaneous measurements of chlorophyll fluorescence suggest that the uptake signals are correlated with energy-dependent fluorescence quenching. Very similar CO2-concentration dependencies are found in the absence and presence of methylviologen, which is known to catalyze O2-reduction, and in the presence of glyceraldehyde, which blocks Calvin cycle and photorespiration. It is suggested that the CO2-enhanced uptake signal is likely to reflect O2-uptake in the Mehler reaction. However, it is not ruled out that also rapid CO2-solubilisation or CO2-binding caused by light-induced stroma alkalisation are involved. Strong uptake is also induced when the CO2-concentration in the closed photoacoustic chamber increases due to dark-respiration. The consequences of these findings with respect to the interpretation of photoacoustic data (e.g., low-light effect) and to the regulatory role of O2-dependent electron flow are discussed. 相似文献
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Zusammenfassung Im Herbst 1984 schliefen mindestens 50 Hohltauben (Columba oenas), wahrscheinlich aber wesentlich mehr, an drei verschiedenen Stellen auf grobscholligen Sturzäckern der offenen Ackerlandschaft des Marchfeldes östlich von Wien. Bäume verwendeten sie nur als Sammelplatz. Im gleichen Zeitraum war auch ein traditioneller Schlafplatz zusammen mit Türkentauben (Streptopelia decaoto) in einem Wiener Randbezirk (16 km entfernt) benutzt; er lag in einem Gehölz.
Stock Doves (Columba oenas) roosting also in open fields
Summary In autumn 1984, at least 50 — probably many more — Stock Doves roosted in open fields, roughly ploughed, east of Vienna. The nearest trees, 200 metres distant, were used only as perches until darkness approached. Some 16 km distant, another roosting place in trees was shared with Collared Doves (Streptopelia decaocto).相似文献
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Treatment of fibrogenic silica (DQ-12) with Disodium Cromoglycate (DSCG) prior to its in-vitro and in-vivo phagocytosis by alveolar macrophages prevents the destruction of the cells and the fibrosis of lung tissue which are a consequence of phagocytosis. However, the treatment of alveolar macrophages with DSCG before phagocytosis of the silica had no, or a negligible, protective effect on the cells. Acid phosphatase activity which was significantly enhanced above the control in cells phagocytosing the silica was returned to the range found in phagocytosis of inert dust when silica treated with DSCG was phagocytized. The inhibitor of DNA- dependent RNA synthesis actinomycin D caused an increase of acid phosphatase activity. DSCG did not depress the phagocytic ability of alveolar macrophages. It appears that the catabolic enzyme process predominant in cells phagocytosing DQ-12 was under control in cells phagocytosing DQ-12 treated with DSCG and that DSCG probably acted as a regulator of the factors permitting catabolism. From the results it is suggested that the equilibrium of the enzyme reactions which accompany phagocytosis was such that the integrity of the phagocytes was preserved. 相似文献