Evaluation of a clinical scoring system for canine demodicosis     

Berrett Dengler  Ekaterina Mendoza-Kuznetsova  Lyubov Nikolaeva  Anna Rieger  Ralf S. Mueller 《Veterinary dermatology》2021,32(4):311-e84

  相似文献   

Effects of flow variation on channel and floodplain biota and habitats of the Sacramento River,California, USA     

Ted R. Sommer  William C. Harrell  Anke Mueller Solger  Brad Tom  Wim Kimmerer 《水产资源保护:海洋与淡水生态系统》2004,14(3):247-261

• 1. Despite progress in the development of conceptual models of river processes, the validation and application of these models to conservation may be limited by a deficit of tools for intermediate‐scale (1–100km) reaches. A model was developed to examine the effect of variation in flow on the responses of two trophic levels in a large temperate river (Sacramento River) and its seasonal floodplain (Yolo Bypass). Field data and hydrologic simulations were evaluated for three hydrologically diverse years.
• 2. The simulations showed much more hydrologic variability in the floodplain than the river, with greater total surface and shallow area, longer hydraulic residence times, and lower water velocities for the floodplain.
• 3. Chlorophyll a levels were significantly higher in the floodplain than in the river, and were negatively associated with flow. These results were consistent with longer hydraulic residence times, increased surface area of shallow water, and warmer water temperatures.
• 4. Copepods and cladoceran densities were similar in the river and its floodplain, and were mostly negatively associated with flow.
• 5. There were significantly higher densities of Diptera and terrestrial invertebrates in the floodplain than the river. Diptera densities in the floodplain were positively associated with flow.
• 6. These results provide evidence of the incremental value of floodplain habitat to the conservation of large rivers. In particular, it appears that providing river–floodplain connectivity can enhance production of lower trophic levels at relatively rapid time scales, probably benefitting secondary consumers, including Chinook salmon (Onchyrhynchus tshawytscha).

Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Aggregate stability and physical protection of soil organic carbon in semi‐arid steppe soils     

M. Wiesmeier  M. Steffens  C. W. Mueller  A. Kölbl  A. Reszkowska  S. Peth  R. Horn  I. Kögel‐Knabner 《European Journal of Soil Science》2012,63(1):22-31

Spatial inaccessibility of soil organic carbon (SOC) for microbial decay within soil aggregates is an important stabilization mechanism. However, little is known about the stability of aggregates in semiarid grasslands and their sensitivity to intensive grazing. In this study, a combined approach using soil chemical and physical analytical methods was applied to investigate the effect of grazing and grazing exclusion on the amount and stability of soil aggregates and the associated physical protection of SOC. Topsoils from continuously grazed (CG) and ungrazed sites where grazing was excluded from 1979 onwards (UG79) were sampled for two steppe types in Inner Mongolia, northern China. All samples were analysed for basic soil properties and separated into free and aggregate‐occluded light fractions (fLF, oLF) and mineral‐associated fractions. Tensile strength of soil aggregates was measured by crushing tests. Undisturbed as well as artificially compacted samples, where aggregates were destroyed mechanically by compression, were incubated and the mineralization of SOC was measured. For undisturbed samples, the cumulative release of CO₂‐C was greater for CG compared with UG79 for both steppe types. A considerably greater amount of oLF was found in UG79 than in CG soils, but the stabilities of 10–20‐mm aggregates were less for ungrazed sites. Compacted samples showed only a slightly larger carbon release with CG but a considerably enhanced mineralization with UG79. We assume that the continuous trampling of grazing animals together with a smaller input of organic matter leads to the formation of mechanically compacted stable ‘clods’, which do not provide an effective physical protection for SOC in the grazed plots. In UG79 sites, a greater input of organic matter acting as binding agents in combination with an exclusion of animal trampling enhances the formation of soil aggregates. Thus, grazing exclusion promotes the physical protection of SOC by increasing soil aggregation and is hence a management option to enhance the C sequestration potential of degraded steppe soils.  相似文献   

NanoSIMS as a tool for characterizing soil model compounds and organomineral associations in artificial soils     

Katja Heister  Carmen H?schen  Geertje J. Pronk  Carsten W. Mueller  Ingrid K?gel-Knabner 《Journal of Soils and Sediments》2012,12(1):35-47

Purpose  

Secondary ion mass spectrometry at the nanoscale (NanoSIMS) is a new and promising technique in soil science, as it allows us to explore the elemental and isotopic composition of a solid sample with high sensitivity at a submicron scale. In this study, we demonstrate that it is possible to differentiate the major components of soils by this technique.  相似文献   

Plaggic Anthrosol: Soil of the Year 2013 in Germany: An overview on its formation,distribution, classification,soil function and threats          下载免费PDF全文

Luise Giani  Lutz Makowsky  Klaus Mueller 《植物养料与土壤学杂志》2014,177(3):320-329

The Plaggic Anthrosol (German: Plaggenesch) has been elected “Soil of the Year 2013” in Germany. This article reviews present knowledge on the formation, distribution, classification, soil functions, and threats of Plaggic Anthrosols. As the colors of Plaggic Anthrosols differ, we introduce a “Grey Plaggic Anthrosol” and a “Brown Plaggic Anthrosol”. The term Plaggic Anthrosols is used in WRB, whereas those soils are classified as Agrosems according to the Russian, as Plagganthrepts according to the US Soil Taxonomy, and Plaggenesch according to the German taxonomy. The formation of Plaggic Anthrosols is the result of a former arable land use technique, the plaggen agriculture, starting ≈ 1000 y ago and lasting since the introduction of mineral fertilization. During processing plaggen agriculture, plaggen or sods of humic topsoil horizons were cut in the landscape, carried to the stables, enriched with dung, and subsequently spread out onto the fields as an organic‐earthy manure. The manure decomposed and humified, whereas the mineral fraction remained and raised the land surface by 0.1 cm y^–1 in average. Hence, the diagnostic horizon, a thick (70–130 cm) humus‐rich man‐made epipedon, often containing artefacts, was formed over time. The main region of spatial distribution of Plaggic Anthrosols is NW Germany, The Netherlands and NE Belgium. Minor occurrences are reported from other parts of Europe. Compared to the associated soils, Plaggic Anthrosols hold considerable natural, archive and utilization functions, but are threatened by degradation when their use as arable soil is rendered.  相似文献   

Genomic sequencing and methylation analysis by ligation mediated PCR   总被引：72，自引：0，他引：72  

G P Pfeifer  S D Steigerwald  P R Mueller  B Wold  A D Riggs 《Science (New York, N.Y.)》1989,246(4931):810-813

Genomic sequencing permits studies of in vivo DNA methylation and protein-DNA interactions, but its use has been limited because of the complexity of the mammalian genome. A newly developed genomic sequencing procedure in which a ligation mediated polymerase chain reaction (PCR) is used generates high quality, reproducible sequence ladders starting with only 1 microgram of uncloned mammalian DNA per reaction. Different sequence ladders can be created simultaneously by inclusion of multiple primers and visualized separately by rehybridization. Relatively little radioactivity is needed for hybridization and exposure times are short. Methylation patterns in genomic DNA are readily detectable; for example, 17 CpG dinucleotides in the 5' region of human X-linked PGK-1 (phosphoglycerate kinase 1) were found to be methylated on an inactive human X chromosome, but unmethylated on an active X chromosome.  相似文献   

Carbonic anhydrase and osteoclasts: localization by labeled inhibitor autoradiography   总被引：7，自引：0，他引：7  

C V Gay  W J Mueller 《Science (New York, N.Y.)》1974,183(123):432-434

Autoradiography with tritiated acetazolamide indicates that osteoclasts of the hen and chick contain concentrations of carbonic anhydrase which are similar to those in pancreatic acinar cells. Grain counts of osteoblasts and osteocytes were not different from background. Thus, a sufficient quantity of carbonic anhydrase seems to be present in osteoclasts to be of physiological importance in bone resorption.  相似文献   

On Supplementing Human Faculties     

Mueller RE 《Science (New York, N.Y.)》1959,130(3370):298

  相似文献   

Energy analysis     

Mueller RF 《Science (New York, N.Y.)》1976,192(4234):12-11

  相似文献   

Ancient tripartite coevolution in the attine ant-microbe symbiosis     

Currie CR  Wong B  Stuart AE  Schultz TR  Rehner SA  Mueller UG  Sung GH  Spatafora JW  Straus NA 《Science (New York, N.Y.)》2003,299(5605):386-388

The symbiosis between fungus-growing ants and the fungi they cultivate for food has been shaped by 50 million years of coevolution. Phylogenetic analyses indicate that this long coevolutionary history includes a third symbiont lineage: specialized microfungal parasites of the ants' fungus gardens. At ancient levels, the phylogenies of the three symbionts are perfectly congruent, revealing that the ant-microbe symbiosis is the product of tripartite coevolution between the farming ants, their cultivars, and the garden parasites. At recent phylogenetic levels, coevolution has been punctuated by occasional host-switching by the parasite, thus intensifying continuous coadaptation between symbionts in a tripartite arms race.  相似文献