Severe growth abnormalities including shoot stunting, leaf blade reduction and flower bud failure of Brussels sprout were observed in Poland. The presence of phytoplasma in diseased as well as in healthy looking plant...Severe growth abnormalities including shoot stunting, leaf blade reduction and flower bud failure of Brussels sprout were observed in Poland. The presence of phytoplasma in diseased as well as in healthy looking plants, was demonstrated by nested polymerase chain reaction assay employing phytoplasma universal rRNA primer pairs-P1/P7 followed by R16F2n/R16R2. Products of PCR primed by R 16F2n/R 16R2 primer pair from naturally infected Brussels sprouts were sequenced. Comparison of the obtained 16S rDNAs revealed high nucleotide sequence identity between analyzed phytoplasma isolates （99.8%-100%）. They were also nearly identical with the sequences of other phytoplasmas isolates from sub-group 16SrI-B, and they were classified as members of ＂Candidatus Phytoplasma asteris＂.展开更多
Ethiopian coffee price is highly fluctuated and has significant effect on the economy of the country. Conducting a research on forecasting coffee price has theoretical and practical importance.This study aims at forec...Ethiopian coffee price is highly fluctuated and has significant effect on the economy of the country. Conducting a research on forecasting coffee price has theoretical and practical importance.This study aims at forecasting the coffee price in Ethiopia. We used daily closed price data of Ethiopian coffee recorded in the period 25 June 2008 to 5 January 2017 obtained from Ethiopia commodity exchange（ECX） market to analyse coffee prices fluctuation. Here, the nature of coffee price is non-stationary and we apply the Kalman filtering algorithm on a single linear state space model to estimate and forecast an optimal value of coffee price. The performance of the algorithm for estimating and forecasting the coffee price is evaluated by using root mean square error（RMSE）. Based on the linear state space model and the Kalman filtering algorithm, the root mean square error（RMSE） is 0.000016375, which is small enough, and it indicates that the algorithm performs well.展开更多
Non-spreading nature of Bessel spatiotemporal wavepackets is theoretically and experimentally investigated and orders of magnitude improvement in the spatiotemporal spreading has been demonstrated.The spatiotemporal c...Non-spreading nature of Bessel spatiotemporal wavepackets is theoretically and experimentally investigated and orders of magnitude improvement in the spatiotemporal spreading has been demonstrated.The spatiotemporal confinement provided by the Bessel spatiotemporal wavepacket is further exploited to transport transverse orbital angular momentum through embedding spatiotemporal optical vortex into the Bessel spatiotemporal wavepacket, constructing a new type of wavepacket: Bessel spatiotemporal optical vortex. Both numerical and experimental results demonstrate that spatiotemporal vortex structure can be well maintained and confined through much longer propagation. High order spatiotemporal optical vortices can also be better confined in the spatiotemporal domain and prevented from further breaking up, overcoming a potential major obstacle for future applications of spatiotemporal vortex.展开更多
文摘Severe growth abnormalities including shoot stunting, leaf blade reduction and flower bud failure of Brussels sprout were observed in Poland. The presence of phytoplasma in diseased as well as in healthy looking plants, was demonstrated by nested polymerase chain reaction assay employing phytoplasma universal rRNA primer pairs-P1/P7 followed by R16F2n/R16R2. Products of PCR primed by R 16F2n/R 16R2 primer pair from naturally infected Brussels sprouts were sequenced. Comparison of the obtained 16S rDNAs revealed high nucleotide sequence identity between analyzed phytoplasma isolates （99.8%-100%）. They were also nearly identical with the sequences of other phytoplasmas isolates from sub-group 16SrI-B, and they were classified as members of ＂Candidatus Phytoplasma asteris＂.
文摘Ethiopian coffee price is highly fluctuated and has significant effect on the economy of the country. Conducting a research on forecasting coffee price has theoretical and practical importance.This study aims at forecasting the coffee price in Ethiopia. We used daily closed price data of Ethiopian coffee recorded in the period 25 June 2008 to 5 January 2017 obtained from Ethiopia commodity exchange（ECX） market to analyse coffee prices fluctuation. Here, the nature of coffee price is non-stationary and we apply the Kalman filtering algorithm on a single linear state space model to estimate and forecast an optimal value of coffee price. The performance of the algorithm for estimating and forecasting the coffee price is evaluated by using root mean square error（RMSE）. Based on the linear state space model and the Kalman filtering algorithm, the root mean square error（RMSE） is 0.000016375, which is small enough, and it indicates that the algorithm performs well.
文摘Non-spreading nature of Bessel spatiotemporal wavepackets is theoretically and experimentally investigated and orders of magnitude improvement in the spatiotemporal spreading has been demonstrated.The spatiotemporal confinement provided by the Bessel spatiotemporal wavepacket is further exploited to transport transverse orbital angular momentum through embedding spatiotemporal optical vortex into the Bessel spatiotemporal wavepacket, constructing a new type of wavepacket: Bessel spatiotemporal optical vortex. Both numerical and experimental results demonstrate that spatiotemporal vortex structure can be well maintained and confined through much longer propagation. High order spatiotemporal optical vortices can also be better confined in the spatiotemporal domain and prevented from further breaking up, overcoming a potential major obstacle for future applications of spatiotemporal vortex.
