Clonal dominance of hematopoietic stem cells triggered by retroviral gene marking     

Kustikova O  Fehse B  Modlich U  Yang M  Düllmann J  Kamino K  von Neuhoff N  Schlegelberger B  Li Z  Baum C 《Science (New York, N.Y.)》2005,308(5725):1171-1174

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Effect of Acid Aluminous Soil on Photosynthetic Parameters of Potato (Solanum tuberosum L.)     

Boris Lazarević  Tea Horvat  Milan Poljak 《Potato Research》2014,57(1):33-46

Potato is grown worldwide, in some cases in very acid soils. Aluminum (Al) is a major limiting factor for crop productivity in acid soils. Al toxicity was studied mainly on plant roots, while less attention was given to its effects on leaves. Al tolerance observed in solution cultures has rarely been correlated with Al tolerance in acid soils. Al tolerance was assessed in 12 potato cultivars grown in nutrient solutions containing 0, 25, and 50 μmol Al L^?1 by its relative root elongation (RRE). The effect of acid soil with high level of exchangeable Al on leaf mineral content, chlorophyll content, net photosynthetic rate, transpiration rate, stomatal conductance, intercellular CO₂ concentration, water use efficiency (WUE), and light use efficiency (LUE) was studied on cultivars, with the greatest differences in RRE (cv. Tresor, 63.1 and 42.5% and cv. Canberra, 23.3 and 19.2%, for the 25 and 50 μmol Al L^?1 treatments, respectively), grown for 49 days after planting (DAP) in acid and limed soil. Growth in acid soil significantly reduced concentrations of nitrogen (?18.51%) and magnesium (?27.17%) in the leaves in cv. Canberra and concentrations of potassium and copper in both cultivars. Canberra grown in acid soil showed a significant decrease in chlorophyll content and photosynthetic rate, from 28 to 49 DAP, and in transpiration rate and LUE when averaged across all measurements, while cv. Tresor was not affected. Physiological disorders observed on leaves of plants grown in acid soil can be correlated with the differences in Al tolerance observed in nutrient solutions.  相似文献   

Modelling macronutrients in shelf sea sediments: fitting model output to experimental data using a genetic algorithm     

Christopher C. Wood  Peter J. Statham  Boris A. Kelly-Gerreyn  Adrian P. Martin 《Journal of Soils and Sediments》2014,14(1):218-229

Purpose

Diagenetic modelling, the mathematical simulation of the breakdown of sedimentary organic matter and subsequent fate of associated nutrients, has progressed to a point where complex, non-steady state environments can be accurately modelled. A genetic algorithm has never been used in conjunction with an early diagenetic model, and so we aim to discover whether this method is viable to determining a set of realistic model parameters, which itself is often a difficult task.

Materials and methods

A range of sensitivity analyses were conducted to establish the parameters for which the model was most sensitive before a micro-genetic algorithm (μGA) was used to fit an output from a previously published diagenetic model (OMEXDIA) to observational data, taken at the North Dogger site from a series of cruises in the North Sea. Profiles of carbon, oxygen, nitrate and ammonia were considered. The method allows a set of parameters to be determined in a manner analogous to natural selection. Each iteration of the genetic algorithm within each experiment decreases the variance between the observed profiles and those calculated by OMEXDIA.

Results and discussion

Despite some of the observed profiles, particularly for carbon, showing unusual patterns, the genetic algorithm was able to generate a set of parameters which was able to fit the observations. The genetic algorithm can therefore help to determine the values of other parameters used in the model, for which observational values are difficult to measure (e.g. the flux of organic matter to the sediment from the overlying water column and the rates of degradation of organic matter). We also show that the values of the parameters determined by the μGA technique are able to be used in a potentially temporally predictive manner.

Conclusions

The μGA used is a viable method to fit carbon and nutrient sedimentary profiles observed in complex, dynamic shelf sea systems, despite OMEXDIA originally being designed for a different sedimentary environment. The results therefore show that this novel use of a genetic algorithm is a suitable method for both model calibration and validation and that the technique may help in explaining processes which are poorly understood.  相似文献   

Some factors affecting regional differentiation of the soils in the Republic of Benin (West Africa)     

Paul Faure  Boris Volkoff 《CATENA》1998,32(3-4)

Spatial distribution of the parent materials, color, clay-eluviated horizon thickness, textural profile type, presence and position of the ferruginous nodules and ferricretes in the profile are analyzed at a small scale using the thematic information content of the published 1:200,000 soil map of Benin. Analyses indicate that there is a regional differentiation of the soil cover which is first drawn on that of the geological provinces, sedimentary basins, great morpho-structural units, and then determined by the factors that control the preservation or the transformation and erosion of an ancient lateritic mantle. These factors are directly influenced by differential changes of the local base levels.  相似文献   

Antifungal activities of silver and selenium nanoparticles stabilized with different surface coating agents     

Karolina Vrande i&#x;  Jasenka &#x;osi&#x;  Jelena Ili&#x;  Boris Ravnjak  Ati&#x;a Selmani  Emerik Gali&#x;  Barbara Pem  Rinea Barbir  Ivana Vinkovi&#x; Vr ek  Tomislav Vinkovi&#x; 《Pest management science》2020,76(6):2021-2029

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Fucosylated Chondroitin Sulfates from the Sea Cucumbers Paracaudina chilensis and Holothuria hilla: Structures and Anticoagulant Activity     

Nadezhda E. Ustyuzhanina  Maria I. Bilan  Andrey S. Dmitrenok  Alexandra S. Silchenko  Boris B. Grebnev  Valentin A. Stonik  Nikolay E. Nifantiev  Anatolii I. Usov 《Marine drugs》2020,18(11)

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