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91.
The aim of this study was to develop an anatomical model of the feline hip joint for low‐field magnetic resonance imaging (LF‐MRI) based on high‐field magnetic resonance imaging (HF‐MRI). The study was performed on six adult clinically healthy European shorthair cats, aged 1–3 years, with body weight of 2.8–4.4 kg. The animals were examined with the use of the Vet‐MRI Grande Esaote LF (0.25 T) scanner and high‐field Siemens Magnetom TRIO (3 T) MRI scanner. In the LF‐MRI, most satisfactory results in T1‐weighted images were obtained when TE was 26 ms in all three planes and when TR was 350–950 ms in the transverse plane, 950–1150 ms in the sagittal plane and 520–750 ms in the dorsal plane. In T2‐weighted images, TE was 90 ms in the transverse and dorsal plane and 120 ms in the sagittal plane. The results were presented as images acquired with LF‐MRI scanners in three planes. The slice thickness was 3 mm for each plane. In LF‐MRI, muscles in the hip joint region and round ligament were well visualized. Unlike in LF‐MRI, the cross section of the femoral nerve was identified in HF‐MRI scans. In examinations of the feline hip joint, the main limitations of LF‐MRI were a lack of reliable contrast between articular cartilage and synovial fluid as well as longer scan time. Despite the above, LF‐MRI images were characterized by good contrast between bones and the surrounding soft tissues.  相似文献   
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Xanthomonas fragariae is the causative agent of angular leaf spot of strawberry, a quarantine organism in plant propagation material in the European Union. Field experiments were conducted to assess the risks for infection of strawberry plants through dispersal of an aerosolized inoculum. In practice, pathogen aerosols can be formed during mowing of an infected crop or by water splashing on symptomatic plants during overhead irrigation or rain. In our experiments, aerosols were generated by spraying suspensions of X. fragariae with a density of 108 cfu ml?1 or water under pressure vertically up into the air. In strawberry plants (cv Elsanta) placed at 1.3, 5 and 10 m distance downwind from the spray boom, infections were found, as evidenced with a combination of dilution–plating and molecular techniques, but more frequently in plants wetted prior to inoculation than in plants kept dry. A logarithmic decrease in infection incidence was found with the distance to the inoculum source. Symptomatic plants were found up to 5 m distance from the inoculum source. No infected plants were found in plants placed 4 m upwind or treated with water. In glasshouse studies, it was shown that under conditions favorable for disease development, spray-inoculation of strawberry plants with estimated densities of X. fragariae as low as 2000 cfu per plant were able to cause symptoms both in cv Elsanta and cv Sonata. Results indicate that there is a considerable risk on infections of strawberry plants exposed to aerosolized inoculum.  相似文献   
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Past land‐use changes, intensive cropping with large proportions of root crops, and preferred use of mineral fertilizer have been made responsible for proceeding losses of soil organic C (SOC) in the plough layer. We hypothesized that in intensive agriculturally managed regions changes in SOC stocks would be detectable within a decade. To test this hypothesis, we tracked the temporal development of the concentrations and stocks of SOC in 268 arable sites, sampled by horizon down to 60 cm in the Cologne‐Bonn region, W Germany, in 2005 and in 2013. We then related these changes to soil management data and humus balances obtained from farmers' surveys. As we expected that changes in SOC concentrations might at least in part be minor, we fractionated soils from 38 representative sites according to particle size in order to obtain C pools of different stability. We found that SOC concentrations had increased significantly in the topsoil (from 9.4 g kg?1 in 2005 to 9.8 g kg?1 in 2013), but had decreased significantly in the subsoil (from 4.1 g kg?1 in 2005 to 3.5 g kg?­1 in 2013). Intriguingly, these changes were due to changes in mineral‐bound SOC rather than to changes in sand‐sized organic matter pools. As bulk density decreased, the overall SOC stocks in the upper 60 cm exhibited a SOC loss of nearly 0.6 t C (ha · y)?1 after correction by the equivalent soil mass method. This loss was most pronounced for sandy soils [?0.73 t SOC (ha · y)?1], and less pronounced for loamy soils [?0.64 t SOC (ha · y)?1]; silty soils revealed the smallest reduction in SOC [?0.3 t SOC (ha · y)?1]. Losses of SOC occurred even with the overall humus balances having increased positively from about 20 kg C (ha · y)?1 (2003–2005) to about 133 kg C (ha · y)?1 (2005–2013) due to an improved organic fertilization and intercropping. We conclude that current management may fail to raise overall SOC stocks. In our study area SOC stocks even continued to decline, despite humus conservation practice, likely because past land use conversions (before 2005) still affect SOC dynamics.  相似文献   
97.
Boron detection in soil extracts by inductively-coupled plasma optical-emission spectrometry (ICP-OES) can be influenced by iron interference, particularly in strongly weathered tropical forest soils. Boron concentrations in Mehlich-III extracts of 230 soils under lowland tropical forest in Panama were markedly overestimated at the most sensitive ICP-OES wavelength (249.772 nm) compared to a less sensitive but interference-free wavelength (208.957 nm) due to iron interference. Hot-water extracts contained insufficient iron to interfere in boron detection, but boron quantification in total element digests was affected strongly by iron interference at 249.772 nm. The relationship between boron overestimation and iron was used to correct a database of 300 Mehlich-III extractable boron measurements made at 249.772 nm for soils from a large forest dynamics plot. We recommend that boron measurements in tropical forest soils by ICP-OES should use the less sensitive 208.957 nm wavelength to avoid interference by extracted iron.  相似文献   
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TaqMan assays were developed for the detection of seven Dickeya species, namely D. dianthicola, D. dadantii, D. paradisiaca, D. chrysanthemi, D. zeae, D. dieffenbachiae and D. solani. Sequences of the gene coding for dnaX were used for the design of primers and probes. In studies with axenic cultures of bacteria, the assays were highly specific and only reacted with strains of the target species, and not with non-target bacteria, including those belonging to other Dickeya species and other genera. The detection thresholds for DNA extracted from pure cultures of target strains ranged from 10 to 100 fg. The TaqMan assays for D. dianthicola and D. solani were more extensively evaluated as part of a method validation procedure. The threshold level for target bacteria added to a potato peel extract diluted ten-times in a semi-selective broth, was strain dependent and ranged from 1,000 to 100,000 cfu/ml. The coefficients of variation for repeatability and reproducibility were low and results were largely independent of the type of substrate, i.e. potato tuber or carnation leaf extracts. However, during routine testing of seed potatoes, false-positive reactions were found with the assay for D. solani. The use of the TaqMan assays for inspection of plant propagation material, ecological studies and studies on the effect of control strategies in disease management strategies is discussed.  相似文献   
100.
The aims of this study were to examine the skeleton of domesticated budgerigars of phenotypically different breeding types, to describe the expression of skeletal changes and to discuss the results with special reference to the causes and effects of breed-conditioned alterations. Complete skeletons of 39 adult budgerigars of both sexes were the object of our research. The examinations demonstrated that almost all metrically sized skeleton dimensions of budgerigars of the exhibition type were increased significantly, compared with those of the non-exhibition type. Only for the scapula significant length differences between the budgerigars of both breeding types could not be verified. It can be stated that the measuring parameters 'occipital width', 'maxilla length', 'skull length' and 'prefrontal width' are suitable for the characterization of exhibition budgerigars. However, sexual dimorphisms could be verified in only three parameters (width of the pars symphysialis mandibulae, height of the skull, width of the skull within the range of the occiput). It has to be clarified in future studies to what extent the changes in the skeleton of budgerigars of the exhibition type have already had consequences for their flying ability, metabolism, health and well-being.  相似文献   
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