Quantum properties of dichroic silicon vacancies in silicon carbide

The controlled generation and manipulation of atom-like defects in solids has a wide range of applications in quantum technology. Although various defect centres have displayed promise as either quantum sensors, single photon emitters or light-matter interfaces, the search for an ideal defect with multi-functional ability remains open. In this spirit, we investigate here the optical and spin properties of the V1 defect centre, one of the silicon vacancy defects in the 4H polytype of silicon carbide (SiC). The V1 centre in 4H-SiC features two well-distinguishable sharp optical transitions and a unique S=3/2 electronic spin, which holds promise to implement a robust spin-photon interface. Here, we investigate the V1 defect at low temperatures using optical excitation and magnetic resonance techniques. The measurements, which are performed on ensemble, as well as on single centres, prove that this centre combines coherent optical emission, with up to 40% of the radiation emitted into the zero-phonon line (ZPL), a strong optical spin signal and long spin coherence time. These results single out the V1 defect in SiC as a promising system for spin-based quantum technologies

Cytogenetic and molecular responses of ammonium sulphate application for tolerance to extreme temperatures in Vicia faba L.

Effects of ammonium sulphate [(NH4)(2)SO4] on mitosis, cell cycle and chromosomes in Vicia faba L. seeds exposed to extreme temperatures were investigated using flowcytometric and cytogenetic analysis. Seeds germinated at high and low temperatures showed a significant decrease in mitotic index as compared to those of optimum temperature conditions. Application of 50 and 1000 mu M (NH4)(2)SO4 were successful in alleviating the negative effects of low and high temperature on mitotic activity, respectively. 50 mu M (NH4)(2)SO4 showed the most positive effect on cell cycle at the extreme temperatures. This concentration increased the cell division removing or decreasing the negative effects of temperature stress. Namely, the highest G2/M and S phase percentages under stress conditions were obtained with application of 50 mu M (NH4)(2)SO4. Chromosomal aberrations were not observed in cells of seeds germinated in distilled water and also at any temperatures. However, the frequency of chromosomal aberrations increased significantly by increasing (NH4)(2)SO4 concentration. The highest aberration frequency in all temperature degree tested was found at 1000 mu M (NH4)(2)SO4 concentration.Department of Scientific Research Project Management of Suleyman Demirel University (SDUBAP)Suleyman Demirel University [1636-YL-08]The authors thank the Department of Scientific Research Project Management of Suleyman Demirel University (SDUBAP) for the financial support of the project SDUBAP (1636-YL-08). Thanks also to Dr. Gulderen Yanikkaya DEMIREL and Mehtap OZDEMIR (Istanbul Centro Laboratory Flowcytometry Department, Istanbul, Turkey) for its help in flow cytometric study

Reading and spelling acquisition in Thai children

Thai, a tonal language, has its own distinctive alphabetic orthography.The study investigates reading and spelling development in Thai children, with anaim of examining the grain size that is predominantly used when reading andspelling. Furthermore, word and nonword lists were developed to examine theacquisition of the complex system of vowels and tone rules in Thai. Reading andspelling of words and nonwords were assessed in 60 Thai children ranging in agefrom 7 to 9 years 8 months from Grade(s) 1, 2, and 3. A lexicality effect was foundfor both reading and spelling. Spelling lagged behind reading in the Grade 1 children. Development rapidly increased between the youngest Grade 1 children and theolder Grade 2 and 3 children. For word reading there were significantly more lexicalerrors than phonological errors. Beginning readers appear to predominantly use alarger lexico-syllabic grain size to read Thai