175 research outputs found
Greek wh-Questions and the Phonology of Intonation
No full textThe intonation of Greek wh-questions consists of a rise-fall followed by a low plateau and a final rise. Using acoustic data, we show (i) that the exact contour shape depends on the length of the question, and (ii) that the position of the first peak and the low plateau depends on the position of the stressed syllables, and shows predictable adjustments in alignment, depending on the proximity of adjacent tonal targets. Models that specify the F0 of all syllables, or models that specify F0 by superposing contour shapes for shorter and longer domains, cannot account for such fine-grained lawful variation except by using ad hoc tonal specifications, which, in turn, do not allow for phonological generalisations about contours applying to utterances of greatly different lengths. In contrast, our findings follow easily from an autosegmental-metrical approach to intonational phonology, according to which melodies may contain long F0 stretches derived by interpolation between specified targets associated with metrically strong syllables and prosodic boundaries
<abstruct>A method for the sterile culture of housefly larvae, Musca domestica L ; The influence of spray programs on the fauna of apple orchards in Nova Scotia, V. The predacious thrips ; Rearing the Cadelle Tenebroides mauritanicus (L.)(Coleoptera: Ostomidae) as a Test Insect for Insecticidal Research ; The relative control values of different percentage mortalities
No full textA study on harmonic power of lead type operating circuit for high pressure mercury discharge lamp.
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Characterization of Escherichia coli Persisters from Biofilm Culture: Multiple Dormancy Levels and Multigenerational Memory in Formation
No full textPersister cells (PCs), a subpopulation occurring within normal cells, exhibit a transient tolerance to antibiotics because of their dormant state. PCs are categorized into two types: type I PCs, which emerge during the stationary phase, and type II PCs, which emerge during the logarithmic phase. Using the conventional colony-forming method, we previously demonstrated that type I PCs of Escherichia coli form more frequently in air–solid biofilm culture than in liquid culture. In the current study, we modified a cell filamentation method as a more efficient and rapid alternative for quantifying PCs. This modified method yielded results consistent with those of the conventional method with 103–104 times higher sensitivity and less detection time, within several hours, and further revealed the existence of multiple levels of type I PCs, including a substantial number of deeply dormant cells. This study also discovered a potential epigenetic memory mechanism, spanning several generations (four or six cell divisions), which influences type II PC formation based on prior biofilm experience in E. coli
Large-scale DNA barcode library generation for biomolecule identification in high-throughput screens
No full textHigh-throughput screens allow for the identification of specific biomolecules with characteristics of interest. In barcoded screens, DNA barcodes are linked to target biomolecules in a manner allowing for the target molecules making up a library to be identified by sequencing the DNA barcodes using Next Generation Sequencing. To be useful in experimental settings, the DNA barcodes in a library must satisfy certain constraints related to GC content, homopolymer length, Hamming distance, and blacklisted subsequences. Here we report a novel framework to quickly generate large-scale libraries of DNA barcodes for use in high-throughput screens. We show that our framework dramatically reduces the computation time required to generate large-scale DNA barcode libraries, compared with a naїve approach to DNA barcode library generation. As a proof of concept, we demonstrate that our framework is able to generate a library consisting of one million DNA barcodes for use in a fragment antibody phage display screening experiment. We also report generating a general purpose one billion DNA barcode library, the largest such library yet reported in literature. Our results demonstrate the value of our novel large-scale DNA barcode library generation framework for use in high-throughput screening applications
Identification of a novel DNA element that promotes cell-to-cell transformation in Escherichia coli
No full textAbstractRecently, we discovered a novel phenomenon, “cell-to-cell transformation” by which non-conjugative plasmids are transmitted horizontally in co-cultures of Escherichia coli F− strains. In this study, we aimed to identify the DNA element responsible for the high cell-to-cell transformability of pHSG299. By transplanting pHSG299 DNA fragments into pHSG399, a plasmid showing low transformability, we discovered that a specific 88bp fragment of pHSG299 significantly promoted pHSG399 transformability. Although several short motif-like repetitive sequences (6–10bp) were present in the 88bp sequence, no known DNA motifs were recognized, suggesting that this 88bp sequence (cell-to-cell transformation promoting sequence, CTPS; Accession number: AB634455) is a novel DNA element
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