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The article presents results of a case study in northeastern Germany, where magnetic susceptibility assessment was carried out at grid-wise field measurements. The measurements were clustered into three different depth levels, which represent the humus layer, the transition zone between humus layer and mineral horizon, and the mineral horizon. Taking these three depth levels, a multiple regression-based regionalization approach was applied, testing and using additional environmental parameters derived from geology, topography, and stand type with the aim to develop a comprehensive model for spatial variability of magnetic susceptibility. Spatial variation of magnetic susceptibility was predicted with a high precision by the multiple linear regression models. A slightly differing set of model parameters was selected for the single depth levels. In tendency, magnetic susceptibility values in depth level 6–10 cm were best explained by the distance to Bitterfeld and by soil properties. In depth level 11–15 cm, variables which describe the orographic conditions and stand properties gain in importance. In depth level 21–25 cm, variables indicating soil and site properties disappear completely. Here, aspect and land surface characteristics play a major role together with stand properties. A spatial stratification of the model for a distance of up to 25 km to the former emitters provided a further improvement of the model quality considering the prediction of small-scale variations of magnetic susceptibility.  相似文献   
143.
The indigenous cattle population of Benin is a diverse mix of taurine and hybrid breeds shaped by diverse ecological and climatic conditions with eight agro-ecological zones (AEZ). Presumably, the taurine breeds face current endangerment due to ongoing indicine introgression following climate change and transboundary transhumance. The aim of the study was to investigate the genetic diversity and population structure of the indigenous breeds Lagune, Somba, Pabli and Borgou considering spatial agro-ecological and socio-economic factors (transhumance) based on 50k SNP and microsatellite data. Among the four sampled breeds, six genetic clusters were identified using model-free (discriminant analysis of principal components) and model-based (TESS and ADMIXTURE) methods separating taurine from hybrid breeds. Results based on an extension with publicly available historic SNP data sets from taurine and indicine West African cattle and additional outgroups provided additional insight into changes of genetic structure in the sampled breeds over time. Both taurine breeds, Somba and Lagune, showed a stable foundation but also spatially limited partial indicine introgression associated with transhumance leading to high genetic diversity. In addition, we found evidence for spatial diversity and changes in genetic structure over time in the Borgou breed in comparison of our samples with the historic samples which could be explained by potential continuous indicine introgression into the Borgou breed in two sample regions. Results for the Pabli breed do not conclusively point to full absorbance by the Borgou in comparison with all available Borgou samples. Further research is needed in this regard.  相似文献   
144.
Organic farming often counteracts the decline of various taxa owing to agricultural intensification, but little is known about the relative importance of local management and landscape context for small mammals. We examined the abundance, species richness and diversity of small mammal communities in 22 organically and conventionally managed winter wheat fields pairwise located along a gradient of landscape structural complexity (41–94% arable land). Complex landscapes significantly increased small mammal abundance and (with marginal significance) species richness and diversity, but only in conventional fields, whereas organic farming increased small mammals in simple landscapes. These results indicate the importance of landscape complexity for small mammal populations in an intensified agriculture. Analyses at multiple spatial scales (100 m, 250 m, 500 m radii around focal fields), showed opposing responses of the three most abundant species to landscape complexity. Apodemus agrarius PALLAS abundance increased with increasing landscape complexity at a spatial scale of 100 m, whereas Microtus arvalis PALLAS and Sorex araneus L. abundances decreased with increasing landscape complexity at spatial scales of 100 m and 500 m, respectively, suggesting species-specific ecological needs as well as functional spatial scales for conservation management. In conclusion, agri-environmental measures for small mammals such as organic farming are most effective in simple landscapes, while complex landscapes presumably function as source habitats and can compensate for local agricultural intensification in conventional fields.  相似文献   
145.
Amaranthus hybridus and Amaranthus mantegazzianus are commonly cultivated and the entire young fresh plants consumed as vegetables in regions of Africa and Asia. A. hybridus and A. mantegazzianus were cultivated at four sites in three climate regions of the world: Santa Rosa, Argentina; Lleida, Spain; and Prague and Olomouc, both in the Czech Republic. The contents of flavonoids (isoquercitrin, rutin, nicotiflorin), hydroxybenzoic acids (protocatechuic acid, 4-hydroxybenzoic acid, vanillic acid), hydroxycinnamic acids (caffeic acid, p-coumaric acid, ferulic acid), hydroxycinnamyl amides (N-trans-feruloyltyramine, N-trans-feruloyl-4-O-methyldopamine), and betaines (glycinebetaine, trigonelline) were determined. The variation in phytochemical content due to species and cultivation site was analyzed utilizing the multivariate statistical methods of principal component analysis (PCA) and graphical model (GM). The Argentinean samples differed from the three other locations due to higher contents of most compounds. The samples from Spain and the Czech Republic differed from each other in the content of the negatively correlated metabolites trigonelline and the flavonoids. The two amaranth species were separated primarily by a higher content of trigonelline and the two hydroxycinnamyl amides in A. mantegazzianus. The GM showed that the quantities of the different analytes within each compound group were intercorrelated except in the case of the betaines. The betaines carried no information on each other that was not given through correlations with other compounds. The hydroxycinnamic acids were a key group of compounds in this analysis as they separated the other groups from each other (i.e., carried information on all of the other groups). This study showed the contents of polyphenols and betaines in the aerial parts of vegetable amaranth to be very dependent on growth conditions, but also revealed that some of the compounds (trigonelline and the two hydroxycinnamyl amides) may be useful as features of a taxonomic classification.  相似文献   
146.
Many studies were conducted measuring the lethal concentration of pollutants by using a contaminated solution or polluted sediments. Considering the impact of polluted food on mortality and uptake quantity of invertebrate shredders in batch cultures, little is known about, e.g. uranium and cadmium. Consequently, we investigated in situ the impact of metal and metalloid polluted food and water on Gammarus pulex L. under nature-like conditions. In contrast to other publications, a very low mortality rate of the invertebrates was found. Furthermore, fixation of elements by G. pulex was shown to be low compared to initial concentrations. Fixation of non essential metals and metalloids is shown to take place mainly on the surface of the invertebrates. This is deduced from easy desorption of a relevant amount of fixed metals and metalloids. It is concluded that the accumulation of metals and metalloids in situ under nature-like conditions within the food web via invertebrate shredders is very low. The invertebrates seem to minimize the uptake of non essential elements in the presence of nutrient-rich food even in habitats with higher contamination levels. Hence, invertebrates seem to be adapted to higher contamination levels in their favourable habitats.  相似文献   
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148.
A 46-yr-old male white rhinoceros (Ceratotherium simum) died during anesthesia following agonal excitation. On postmortem, a well-demarcated 2.5-cm tan mass was identified in the right adrenal gland. Histopathology confirmed the presence of a pheochromocytoma, and elevated levels of epinephrine in serum collected shortly prior to the animal's death, as compared with sera from healthy controls, demonstrated the functional nature of the tumor. Although rare, pheochromocytoma should be considered as a differential diagnosis in cases of suspected hypertension and acute death in rhinos.  相似文献   
149.
Previous attempts have shown the potential of T cells in immunotherapy of cancer. Here, we report on the clinical activity of a bispecific antibody construct called blinatumomab, which has the potential to engage all cytotoxic T cells in patients for lysis of cancer cells. Doses as low as 0.005 milligrams per square meter per day in non-Hodgkin's lymphoma patients led to an elimination of target cells in blood. Partial and complete tumor regressions were first observed at a dose level of 0.015 milligrams, and all seven patients treated at a dose level of 0.06 milligrams experienced a tumor regression. Blinatumomab also led to clearance of tumor cells from bone marrow and liver. T cell-engaging antibodies appear to have therapeutic potential for the treatment of malignant diseases.  相似文献   
150.
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