A method to generate soilscapes from soil maps

Digital soil mapping for large areas is challenging if mapping resolution should be as high as possible and sampling should be as sparse as possible. Generally, the more complex the soil associations in a landscape, the more samples are required to systematically cover the entire feature space. Moreover, regions should be modeled separately if the patterns of spatial variation vary on subregion level. A systematic segmentation of a landscape into soilscapes is additionally important for a feasible application of soil‐sensing approaches. In this paper, we introduce a semiautomated approach to segment nominal spatial datasets based on the local spatial frequency distribution of the mapping units. The aim is to provide homogeneous and nonfragmented segments with smoothed boundaries. The methodological framework for the segmentation comprises different spatial and nonspatial techniques and focuses mainly on a moving‐window analysis of the local frequency distribution and a k‐means cluster analysis. Based on an existing soil map (1:50,000), we derived six segments for the Nidda catchment (Central Hesse, Germany), comprising 1600 km². As segmentation is based on a soil map, soilscapes are derived. In terms of the feature space, these soilscapes show a higher homogeneity compared to the entire landscape. Advantages compared to an existing map of landscape units are discussed. Segmenting a landscape as introduced in this study might also be of importance for other disciplines and can be used as a first step in biodiversity analysis or setting up environmental‐monitoring sites.     

Effects of betamethasone treatment on central myelination in fetal sheep: an electron microscopical study

The long-term effect of betamethasone on the myelination of commissural and associational fibres was investigated in fetal sheep. We studied the corpus callosum and subcortical white matter by electron microscopy. Axons were subdivided into classes according to their axonal diameter: class I: < or =0.65 microm; class II: 0.66-0.84 microm; class III: > or =0.85 microm. Under control conditions, the different functions of the white matter tracts examined were reflected by three morphological criteria: (1) there was a diverse percentage of axonal classes in the investigated areas. In corpus callosum the axons of class II predominate (47.1%). In the subcortical white matter, class I axons with small diameter are in majority (40.8%). (2) In the subcortical white matter more axons are present, with especially large diameter and hence of axonal class III. (3) The axons of subcortical white matter have thicker myelin sheaths than those of the corpus callosum. Betamethasone administration caused a significant decrease of class II axons in the corpus callosum (36.9%). In corpus callosum, axons of all classes present thicker myelin sheaths. Betamethasone administration resulted in a change in the formation of the myelin sheath in the commissural fibres of the corpus callosum but not in the associational fibres of the subcortical white matter. This could be the morphological correlate to behavioral and cognitive changes known to occur in humans after prenatal glucocorticoid treatment.     

Cassini dust measurements at Enceladus and implications for the origin of the E ring

During Cassini's close flyby of Enceladus on 14 July 2005, the High Rate Detector of the Cosmic Dust Analyzer registered micron-sized dust particles enveloping this satellite. The dust impact rate peaked about 1 minute before the closest approach of the spacecraft to the moon. This asymmetric signature is consistent with a locally enhanced dust production in the south polar region of Enceladus. Other Cassini experiments revealed evidence for geophysical activities near Enceladus' south pole: a high surface temperature and a release of water gas. Production or release of dust particles related to these processes may provide the dominant source of Saturn's E ring.     

Earthquake potential along the northern hayward fault, california

The Hayward fault slips in large earthquakes and by aseismic creep observed along its surface trace. Dislocation models of the surface deformation adjacent to the Hayward fault measured with the global positioning system and interferometric synthetic aperture radar favor creep at approximately 7 millimeters per year to the bottom of the seismogenic zone along a approximately 20-kilometer-long northern fault segment. Microearthquakes with the same waveform repeatedly occur at 4- to 10-kilometer depths and indicate deep creep at 5 to 7 millimeters per year. The difference between current creep rates and the long-term slip rate of approximately 10 millimeters per year can be reconciled in a mechanical model of a freely slipping northern Hayward fault adjacent to the locked 1868 earthquake rupture, which broke the southern 40 to 50 kilometers of the fault. The potential for a major independent earthquake of the northern Hayward fault might be less than previously thought.     

Factors affecting the collection and fitting of nuclear magnetic cross-relaxation spectroscopy data with application to waxy corn starch

An examination of the methods for nuclear magnetic cross-relaxation spectroscopy (CRS) data collection and analysis was conducted using water and an aqueous waxy corn starch suspension to better perform and interpret the results obtained using CRS. The CRS data collection properties evaluated were the time to achieve steady state saturation, the direct saturation of liquid protons, generation of transverse magnetization, and dependence of the offset frequency and radio frequency (RF) field strength of longitudinal relaxation in the presence of RF saturation. Effects were evaluated for variations of input values of RF saturation field strength, apparent cross-relaxation rate, and solid longitudinal relaxation rate on the results for solid content and solid internal mobility from fitting NMR data to modified theoretical expressions. Discrepancies between fitted and stoichiometric values for the solid to liquid proton ratio were investigated. The fitting procedure used a Gaussian line shape for RF saturation of the solid-like spin system and a Lorentzian line shape for RF saturation of the liquid-spin system. Conditions under which acceptable results can be obtained with limited data sets are discussed.     

The influence of fertilization and rotation on soil organic matter and plant yields in the long‐term Eternal Rye trial in Halle (Saale), Germany

Six forms of fertilizers and three rotations have been examined for 120 years in the ”︁Eternal Rye trial” in Halle (central German arid region, Haplic Phaeozem on sandy loess). Rank analysis, trend analysis and a new component model have been found to be suitable statistical methods to evaluate long‐term results without true replications. In this trial it was shown that mineral fertilization maintains like farmyard manuring the yield potential although at lower content of soil organic matter (SOM). Without fertilization, yield decline was greater with potato and silage maize than winter rye (Secale cereale L.). Deficiencies in N fertilization lead immediately, and in PK supply after more than 20 years, to a significant yield decrease which could be quickly compensated by full fertilization. Rye and maize monocultures also resulted in yield decreases. The establishing of new steady states in the turnover of SOM took about 50 years after changes in fertilization. Contrary to rye monoculture, both silage maize monoculture and potato alternating with winter rye caused considerable decomposition of SOM. According to analytical pyrolysis (Py‐FIMS and Py‐GC/MS), fertilization affects the SOM composition more than rotation. Without fertilization, a higher percentage of thermically stable SOM remained in comparison to the FYM soils. The introduction of potato into the rotation enhanced the content of easily decomposable SOM.     

Screening of soil bacteria for plasmids carrying antibiotic resistance

Summary To evaluate the role of plasmids in soil communities antibiotic-resistant bacteria have been isolated from soil. Among them, 419 l-aminopeptidase positive strains (Gram-negative) and 28 l-aminopeptidase negative strains (Gram-positive) were screened for the presence of plasmids. None of the Gram-negative organisms contained plasmids. Among the Gram-positive bacteria plasmid-harboring strains were detected.