Dissipation of Mefenoxam Residue in Watermelon and Soil Under Field Conditions
Mefenoxam is the systemic phenylamide fungicide, which is widely used in controlling phytophthora disease of tomato, cucumber, pepper and watermelon, etc. The dissipation behaviour of mefenoxam residues in watermelons and soils was studied. The whole watermelon, melon flesh and soil matrices of mefenoxam were analyzed by GC–NPD. At three different spiking levels mean recoveries and relative standard deviation from spiked samples in six replicated experiments for each matrix were in the range 89.6–98.2% and 1.5–8.1%, respectively. Under field conditions, mefenoxam dissipation rate was found to be faster in the whole watermelons than in the soils. The results showed that the half lives in whole watermelon and soil from Beijing were 3.9 and 10.0 days, respectively, and the half lives in whole watermelon and soil from Shanxi were 3.7 and 28.4 days.
Structural and functional diversity of soil microbial communities as a result of combined applications of copper and mefenoxam
Abstract The effects of combined application of mefenoxam and copper on soil microbial community structure and function were investigated in laboratory microcosms over 60 days. Mineralisation of 14C-mefenoxam was followed by trapping the evolved 14CO2. The structural diversity of bacterial and fungal communities was assessed by analysing fingerprints of 16S and 18S rRNA genes and transcripts, resolved by denaturing gradient gel electrophoresis (DGGE). The functional status of the microbial community was investigated by measuring the activities of cellobiohydrolase, hemicellulase, β-glucosidase, phosphatase, aminopeptidase, chitinase and laccase. Results showed that copper application had no significant effect on the mineralisation rate of mefenoxam, although only 5.4% of the applied radioactivity was converted to 14CO2. Both copper and mefenoxam exerted selective detrimental effects on sensitive populations of fungi. In contrast, active bacterial populations were not adversely affected; instead new population structure could be observed during the exposure time. Only a few enzymes exhibited noticeable changes as a result of copper and mefenoxam treatments. Of the seven enzymes under investigation, laccase and chitinase showed an increase in their activity, which lasted till the end of the study. Thus, the study revealed a distinct effect of combined application of mefenoxam and copper both on the structural and functional diversity of microorganisms.
Old English Manuscripts in the Early Age of Print: Matthew Parker and his Scribes
Covering the first dedicated program in the study of and publication of Anglo-Saxon texts, my dissertation examines the sixteenth-century origins of medieval studies as an academic discipline. By placing recent scholarship on media, materiality, cognition, and intellectual history in conversation with traditional paleographical methods on medieval and renaissance manuscript culture, I argue for a new way of understanding how early modern scholars studied and presented the medieval past. I take as my focus a corpus of emulative Anglo-Saxon manuscript transcriptions produced under Elizabethan Archbishop Matthew Parker. Equal parts facsimile and edition, these transcriptions are a unique example of early modern scholars navigating the often competing demands of late sixteenth century manuscript and print culture. This dissertation is, in part, an attempt to catalogue and document the extent of Parkerian Anglo-Saxon manuscript transcriptions. Temporally displaced from their source texts, Parker and his scribes directly modified many of the medieval manuscripts they recovered by editing, rebinding, cropping, and annotating them according to their own interpretive desires and publication needs. These transcriptions place Parker’s early modern scribes into the textual community of early medieval scribal culture, but their printed manuscript editions are an attempt to bring medieval documents into contemporary discourse. They developed new typefaces modeled on manuscript exemplars and attempted to reframe the printed version of a medieval text as an authoritative surrogate