97 research outputs found

    Contact-induced Phonological Mergers: Transfer or Approximation

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    Sound changes in a language are considered nearly inevitable consequences of language death. The literature on sound change in obsolescencing languages has focused on whether the changes are internally or externally motivated, between convergent and divergent change and, therefore, the difference between categorical sound shifts and gradient phonetic effects has been overlooked. This paper examines the acoustic correlates of voicing distinctions in the Kurmanji language that investigate the subphonemic variation within a category. The results of a cross-generational acoustic study of Kurmanji showed that unaspirated initial voiceless stops have undergone phonetic change convergent with Persian, the dominant language. This paper argues that sound change in obsolescing languages may manifest substitution or approximation/expansion of phonological categories in the moribund languag

    Electronically preresonant stimulated Raman scattering microscopy in the visible

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    We report an experimental scheme for stimulated Raman scattering (SRS) microscopy with excitation in the visible spectral region. This allows electronically preresonant (epr) SRS microscopy of a broad range of chromophores with sensitivities as low as 1 μM. Our experiment is based on two synchronously near-infrared pumped optical parametric oscillators (OPO). One of the outputs is modulated at a fourth of the repetition rate with a novel broadband electro-optical modulator. Using a combination of spectral focusing and tuning of the OPO, we show the recording of epr-SRS spectra over the whole range of molecular vibrations at a speed up to 20 times faster than classical wavelength tuning. The imaging capabilities of this setup are demonstrated with material scientific and cellular samples

    Characterization of phytoplasmas related to aster yellows group infecting annual plants in Iran, based on the studies of 16S rRNA and rp genes

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    Several annual field crops, vegetables, ornamentals, oilseed crops, and weeds showing phytoplasma diseases symptoms were collected to detect phytoplasmas related to ‘Candidatus Phytoplasma asteris’. The collecting was done in the central regions of Iran. For general detection of phytoplasmas, 16S rRNA gene fragments were amplified using phytoplasma universal primer pair P1/P7 in polymerase chain reaction (PCR) followed by primer pair R16F2n/R16R2 in nested PCR. Then, for finer detection of phytoplasmas related to ‘Ca. P. asteris’, DNA samples were used to extend the rp and tuf gene fragments by PCR using aster yellows group specific primer pairs rp(I)F1A/rp(I)R1A and fTufAy/rTufAy, respectively. Restriction fragment lenght polymorphism (RFLP) analysis of rp gene fragments using digestion with AluI, MseI, and Tsp509I restriction enzymes indicated that aster yellows group related phytoplasmas in these Iranian regions, belong to rpI-B subgroups. Sequence analysis of partial 16S rRNA and rp genes from representative phytoplasma isolates confirmed the RFLP results. This research is the first report of annual plants infected with phytoplasmas related to subgroup rpI-B in Iran
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