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81.
Wolfgang Priester (1924–2005) was one of Germany’s most versatile and quixotic astrophysicists, reinventing himself successively as a radio astronomer, space physicist and cosmologist, and making a lasting impact on each field. We focus in this personal account on his contributions to cosmology, where he will be most remembered for his association with quasars, his promotion of the idea of a nonsingular “big bounce” at the beginning of the current expansionary phase, and his recognition of the importance of dark energy (Einstein’s cosmological constant Λ) well before this became the standard paradigm in cosmology. In memoriam Wolfgang Priester, 22 April 1924 – 9 July 2005  相似文献   
82.
Human activities are accelerating global biodiversity change and have resulted in severely threatened ecosystem services. A large proportion of terrestrial biodiversity is harbored by soil, but soil biodiversity has been omitted from many global biodiversity assessments and conservation actions, and understanding of global patterns of soil biodiversity remains limited. In particular, the extent to which hotspots and coldspots of aboveground and soil biodiversity overlap is not clear. We examined global patterns of these overlaps by mapping indices of aboveground (mammals, birds, amphibians, vascular plants) and soil (bacteria, fungi, macrofauna) biodiversity that we created using previously published data on species richness. Areas of mismatch between aboveground and soil biodiversity covered 27% of Earth's terrestrial surface. The temperate broadleaf and mixed forests biome had the highest proportion of grid cells with high aboveground biodiversity but low soil biodiversity, whereas the boreal and tundra biomes had intermediate soil biodiversity but low aboveground biodiversity. While more data on soil biodiversity are needed, both to cover geographic gaps and to include additional taxa, our results suggest that protecting aboveground biodiversity may not sufficiently reduce threats to soil biodiversity. Given the functional importance of soil biodiversity and the role of soils in human well-being, soil biodiversity should be considered further in policy agendas and conservation actions by adapting management practices to sustain soil biodiversity and considering soil biodiversity when designing protected areas.  相似文献   
83.
In archived samples from the German environmental specimen bank (ESB) organotin compounds including tributyltin (TBT) and triphenyltin (TPT) as well as their potential degradation products were quantified. Muscles of bream (Abramis brama) sampled in the period 1993-2003 from the rivers Rhine, Elbe, Saale, Mulde, Saar, and from Lake Belau (period 1988-2003) were analyzed by gas chromatography/atomic emission detection-coupling after extraction and derivatization. TBT was detected in nearly all samples and a decrease in levels was observed at all sampling sites. At most sites, the reduction seemed to be a result of the ban on the use of TBT-based antifoulants for the application on small boats, which became effective in Germany in 1989. Highest TBT levels were found in fish from the Elbe near Blankenese (470 ng TBT cation per g fresh weight; in 1995) and lowest in bream from Lake Belau (<1 ngg(-1); in 2001 and 2003). Highest TPT levels (253 ngg(-1) in 1993) were also found in bream caught near Blankenese where the occurrence seemed to be correlated to the former use of TPT as co-toxicant in antifoulants. At other sites TPT levels seemed to be correlated to its use as fungicide (e.g. 9 +/- 2 ngg(-1) in bream from Lake Belau in 2001).  相似文献   
84.
Elia AC  Anastasi V  Dörr AJ 《Chemosphere》2006,64(10):1633-1641
This study was carried out in order to assess the effects of disinfectant-treatment on antioxidant response of Cyprinus carpio L. Therefore, enzymatic activities of glutathione S-transferases, glyoxalase I, glyoxalase II, glutathione peroxidases, glutathione reductase, catalase and total glutathione content of carp liver, exposed to surface water treated with three disinfectants for potabilization, sodium hypochlorite, chlorine dioxide and peracetic acid were investigated. Specimens of carp were exposed in four experimental tanks supplied with a continuous water flow from Lake Trasimeno (Italy), three of them treated with constant concentration of sodium hypochlorite, chlorine dioxide and peracetic acid, for 10 and 20 days, while the control tank was supplied with untreated lake water. Differences in biochemical parameters were observed in specimens following exposure to these disinfectants and mainly, chlorine compounds induced marked biochemical variations of carp liver, compared to those induced by peracetic acid treatment. Our results showed that antioxidant parameters of Cyprinus carpio could be used as biomarkers of oxidative stress when this species is exposed to disinfectants for water potabilization.  相似文献   
85.
Photodegradation kinetics of Monuron (3-(4-chlorophenyl)-1,1-dimethylurea) in photoreactor with immobilized and suspended TiO2 photocatalyst were studied. The effect of addition of ferric or ferrous perchlorate was investigated. Whatever the concentration of Fe(III/II) added there is no significant negative effect on the photodegradation rate of pollutants. On the contrary, depending on speciation and concentration of iron salts, slight or marked acceleration of the photodegradation kinetics was observed. This positive influence was more pronounced in the case of TiO2 suspensions than for TiO2 layers. Fe(III) was generally more effective than Fe(II).  相似文献   
86.
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Summary To investigate the dynamics of the winter flock patch exploitation, feeding experiments were performed with 140 semi-tame, free-roaming greylag geese (Anser anser). Three different initial densities of barley were offered on a 50-m2 patch: low (1600 grains/m2), intermediate (3300/m2) and high (I 1500/m2). Goose numbers on the patch, peck rates, and frequencies of agonistic encounters and of alert postures were observed by scanning the flock and in focal individuals. At low and intermediate initial food densities, peck rates decreased with food density, whereas at high food density, peck rates decreased only slightly over the feeding bout. Agonistic interactions increased as food decreased. A switch from exploitation to interference competition occurred at a threshold of approximately 900 remaining grains per square meter. With high initial food density, agonistic encounters began to increase gradually after 20–30 min. The same general patterns were observed for frequency of alertness. Family members occupied the patch for the longest time periods. The family female and the offspring fed most intensely. The family gander however, fed significantly less but was more aggressive and vigilant than all other social categories. Solitary geese spent their time on the patch doing little else but feeding and were the first to leave. It seems that high-ranking families and low-ranking singles adopt different competitive strategies, the former being superior interference competitors whereas the latter are forced scramble competitors.This study is dedicated to the memory of Konrad Lorenz Correspondence to: K. Kotrschal  相似文献   
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90.
Few reports concerning intrauterine shunting are available. We investigated the impact of this method. In order to evaluate intrauterine shunting and the complication rate for different indications, we sent a questionnaire to all German-speaking level 3 centres. In four level 3 centres, 52 intrauterine catheters were inserted in 34 fetuses. The indications were uni- or bilateral hydrothorax in nine cases, cystic adenomatoid malformation of the lung in four cases, infravesical stenosis in 13 cases, and fetal ascites in eight cases. In three cases (6 per cent), difficulties occurred when the drain was inserted. In 15 cases (29 per cent), the function of the drain was reduced by dislocation or occlusion. The mortality rate caused by shunting was as high as eight per cent (four cases). The application of an intrauterine shunt currently represents a rarely performed ultrasound-guided therapeutic intervention in the fetus. In all cases, the indication for shunting is to avoid compression of normal tissue by cystic structures. A high complication rate restricts the application of drainage to selected cases.  相似文献   
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