Science policy. Changing incentives to publish     

Franzoni C  Scellato G  Stephan P 《Science (New York, N.Y.)》2011,333(6043):702-703

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Phylogeny of the SARS coronavirus     

Eickmann M  Becker S  Klenk HD  Doerr HW  Stadler K  Censini S  Guidotti S  Masignani V  Scarselli M  Mora M  Donati C  Han JH  Song HC  Abrignani S  Covacci A  Rappuoli R 《Science (New York, N.Y.)》2003,302(5650):1504-1505

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Degradability of black carbon and its impact on trace gas fluxes and carbon turnover in paddy soils   总被引：2，自引：0，他引：2  

Christian Knoblauch  Arina-Ann Maarifat  Stephan M. Haefele 《Soil biology & biochemistry》2011,43(9):1768-1778

Rice paddy soils are characterized by anoxic conditions, anaerobic carbon turnover, and significant emissions of the greenhouse gas methane. A main source for soil organic matter in paddy fields is the rice crop residue that is returned to fields if not burned. We investigated as an alternative treatment the amendment of rice paddies with rice residues that have been charred to black carbon. This treatment might avoid various negative side effects of traditional rice residue treatments. Although charred biomass is seen as almost recalcitrant, its impact on trace gas (CO₂, CH₄) production and emissions in paddy fields has not been studied. We quantified the degradation of black carbon produced from rice husks in four wetland soils in laboratory incubations. In two of the studied soils the addition of carbonised rice husks resulted in a transient increase in carbon mineralisation rates in comparison to control soils without organic matter addition. After almost three years, between 4.4% and 8.5% of the black carbon added was mineralised to CO₂ under aerobic and anaerobic conditions, respectively. The addition of untreated rice husks resulted in a strong increase in carbon mineralisation rates and in the same time period 77%-100% of the added rice husks were mineralised aerobically and 31%-54% anaerobically. The ¹³C-signatures of respired CO₂ gave a direct indication of black carbon mineralisation to CO_2. In field trials we quantified the impact of rice husk black carbon or untreated rice husks on soil respiration and methane emissions. The application of black carbon had no significant effect on soil respiration but significantly enhanced methane emissions in the first rice crop season. The additional methane released accounted for only 0.14% of black carbon added. If the same amount of organic carbon was added as untreated rice husks, 34% of the applied carbon was released as CO₂ and methane in the first season. Furthermore, the addition of fresh harvest residues to paddy fields resulted in a disproportionally high increase in methane emissions. Estimating the carbon budget of the different rice crop residue treatments indicated that charring of rice residues and adding the obtained black carbon to paddy fields instead of incorporating untreated harvest residues may reduce field methane emissions by as much as 80%. Hence, the production of black carbon from rice harvest residues could be a powerful strategy for mitigating greenhouse gas emissions from rice fields.  相似文献   

Eigenschaften,Entwicklung und Wert rekultivierter Böden aus Löß im Gebiet des Rheinischen Braunkohlen-Tagebaues     

D. Schrder  S. Stephan  H. Schulte-Karring 《植物养料与土壤学杂志》1985,148(2):131-146

Conditions, genesis and value of recultivated loess soils Physical, chemical, microbiological and micromorphological investigations have been executed on recultivated loess soils deposited between 1963 and 1968 and under agriculture since than. The main results are: 1. Dry deposited materials are often strongly compressed at 50-120 cm depth. Wet and dry deposited materials may be compressed at 30-50 cm by tillage. 2. The new soils show already a notable carbonate metabolism, loss of sodium and magnesium and a certain enrichment of humus and potassium. 3. Well recultivated soils are forming fertile Pararendzina soils, whereas the other ones are developing into difficult Pseudogley soils. 4. Land evaluation gives values of 60 to 80. However, fertility is not as high, and 10-15 should be subtracted from the values. 5. In compressed soils, melioration by deep loosening and drainage is the only method to evoid further degradation. It is, however not free from difficulties.  相似文献   

Regional Sediment Deficits in the Dutch Lowlands: Implications for Long-Term Land-Use Options (8 pp)     

Michiel J. van der Meulen  Ad J. F. van der Spek  Ger de Lange  Stephan H. L. L. Gruijters  Serge F. van Gessel  Buu-Long Nguyen  Denise Maljers  Jeroen Schokker  Jan P. M. Mulder  Rob A. A. van der Krogt 《Journal of Soils and Sediments》2007,7(1):9-16

Background, Aim and Scope   Coastal and river plains are the surfaces of depositional systems, to which sediment input is a parameter of key-importance. Their habitation and economic development usually requires protection with dikes, quays, etc., which are effective in retaining floods but have the side effect of retarding sedimentation in their hinterlands. The flood-protected Dutch lowlands (so-called dike-ring areas) have been sediment-starved for up to about a millennium. In addition to this, peat decomposition and soil compaction, brought about by land drainage, have caused significant land subsidence. Sediment deficiency, defined as the combined effect of sediment-starvation and drainage-induced volume losses, has already been substantial in this area, and it is expected to become urgent in view of the forecasted effects of climate change (sea-level rise, intensified precipitation and run-off). We therefore explore this deficiency, compare it with natural (Holocene) and current human sediment inputs, and discuss it in terms of long-term land-use options. Materials and Methods: We use available 3D geological models to define natural sediment inputs to our study area. Recent progress in large-scale modelling of peat oxidation and compaction enables us to address volume loss associated with these processes. Human sediment inputs are based on published minerals statistics. All results are given as first-order approximations. Results: The current sediment deficit in the diked lowlands of the Netherlands is estimated at 136 ± 67 million m3/a. About 85% of this volume is the hypothetical amount of sediment required to keep up with sea-level rise, and 15% is the effect of land drainage (peat decomposition and compaction). The average Holocene sediment input to our study area (based on a total of 145 km3) is ~14 million m3/a, and the maximum (millennium-averaged) input ~26 million m3/a. Historical sediment deficiency has resulted in an unused sediment accommodation space of about 13.3 km3. Net human input of sediment material currently amounts to ~23 million m3/a. Discussion: As sedimentary processes in the Dutch lowlands have been retarded, the depositional system's natural resilience to sea-level rise is low, and all that is left to cope is human countermeasure. Preserving some sort of status quo with water management solutions may reach its limits in the foreseeable future. The most viable long-term solutions therefore seem a combination of allowing for more water in open country (anything from flood-buffer zones to open water) and raising lands that are to be built up (enabling their lasting protection). As to the latter, doubling or tripling the use of filling sand in a planned and sustained effort may resolve up to one half of the Dutch sediment deficiency problems in about a century. Conclusions: Conclusions, Recommendations and Perspectives. We conclude that sediment deficiency – past, present and future – challenges the sustainable habitation of the Dutch lowlands. In order to explore possible solutions, we recommend the development of long-term scenarios for the changing lowland physiography, that include the effects of Global Change, compensation measures, costs and benefits, and the implications for long-term land-use options. Recommendations and Perspectives: -  相似文献   

Detection of potentially allergenic hazelnut (Corylus avellana) residues in food: a comparative study with DNA PCR-ELISA and protein sandwich-ELISA     

Holzhauser T  Stephan O  Vieths S 《Journal of agricultural and food chemistry》2002,50(21):5808-5815

Allergen detection is of increasing interest for food labeling purposes. A comparative study with a commercial hazelnut-specific PCR-ELISA and a sandwich-type ELISA detecting hazelnut protein was performed to investigate to what extent immunochemical and DNA-based techniques would correlate in the detection of trace amounts of potentially allergenic hazelnut residues. Both methods were highly sensitive and allowed the detection of even <10 ppm of hazelnut in complex food matrixes. The protein-ELISA was highly specific for hazelnut. However, some foods could lead to false-positive results at the 10 ppm level. The PCR-ELISA did not show any cross-reactions with non-hazelnut foods, thus reducing the probability of having false positives at the trace level. Forty-one commercial food products with and without hazelnut components on their labels were analyzed for the presence of hazelnut. Of the 27 products in which hazelnut components were detected, two samples were not identified by the protein-ELISA, and only one sample, namely one white chocolate having <1 ppm of hazelnut protein, was not detected by PCR-ELISA. The good correlation of the results of PCR-ELISA and protein-ELISA suggested that both PCR-based and immunochemical techniques are suitable for reliable detection of potentially allergenic hazelnut residues in foods at the trace level.  相似文献   

Characterization of in situ organic matter constituents in vertisols from Argentina, using submicroscopic and cytochemical methods — first report     

S. Stephan  J. Berrier  A.A. De Petre  C. Jeanson  M.J. Kooistra  H.W. Scharpenseel  H. Schiffmann 《Geoderma》1983,30(1-4):21-34

The investigation of residence, alteration and circulation of soil organic matter is an ideal problem for integrated research including microscopy and submicroscopic methods. The subject of the present study is an argillic Pelludert of Argentina. The organic matter in this soil shows an unexpectedly steep gradient of ¹⁴C age. Below 25 cm the frequency of microscopic organic features decreases rapidly. Only few types are present at greater depth. Features produced by faunal activity, as well as brown to black areas of different composition have been investigated with SEM-EDXRA. The main subjects of laserinduced mass spectra were dark grains of few microns diameter which abound in the fine mass. Some spectra are presented and discussed. Further investigations are planned in order to demonstrate how submicroscopy, associated to the physico-chemical methods, can contribute to the knowledge and to the comprehension of the genesis of Vertisols.  相似文献   

Economics and Contemporary Land Use Policy: Development and Conservation at the Rural‐Urban Fringe – Edited by Robert J. Johnston and Stephen K. Swallow     

Stephan Weiler 《Growth and change》2007,38(1):163-166

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The clinical administration of the opioid antagonist naloxone in dogs     

W Erhardt  M Stephan  K Geissd?rfer  M Schindele  R Ascherl  A Stemberger 《Tier?rztliche Praxis》1987,15(2):213-218

The short introduction gives a review on the complex of exogen and endogen opioids and their receptors as well as on their pharmacodynamics, pharmacokinetics and toxicity of naloxone. The clinical efficacy of naloxone as an opioid antagonist is described. Applications of naloxone for the dog are specified: antagonisation of etorphine, morphine, levomethadone and fentanyl, antagonisation of exogen and endogen opioids in puppies and treatment of lactomania in the bitch. The mean effective dose to antagonize morphines is 0.003 mg/kg bodyweight. If persisting analgesia is indicated the dose of naloxone in titrating steps in 0.001 mg/kg bw. To antagonize postpartal hypoxia in puppies 0.02 mg per animal naloxone have to be injected. For treatment of lactomania a dose of 0.01 mg/kg bodyweight twice a day for a couple of days is recommended. The clinical effectivity of naloxone is proved doubtlessly. Compatibility and safety are very high.  相似文献   

The occurrence of antibiotic-resistant coliform germs in the intestinal flora of man and various domestic animals     

R Stephan  E Bulling 《Berliner und Münchener tier?rztliche Wochenschrift》1971,84(2):30-33

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