Development of hybrid rice has greatly contributed to increased yields during the past three decades. Two bentazon-lethal mutants 8077S and Norin8m are being utilized in developing new hybrid rice systems. When the male sterile lines are developed in such a mutant background, the problem of F1 seed contamination by self-seeds from the sterile lines can be solved by spraying bentazon at seedling stage. We first determined the sensitivity of the mutant plants to bentazon. Both mutants showed symptoms to bentazon starting from 100 mg/l, which was about 60-fold, lower than the sensitivity threshold of their wild-type controls. In addition, both mutants were sensitive to sulfonylurea-type herbicides. The locus for the mutant phenotype is bel for 8077S and bsl for Norin8m. Tests showed that the two loci are allelic to each other. The two genes were cloned by map-based cloning. Interestingly, both mutant alleles had a single-base deletion, which was confirmed by PCR-RFLP. The two loci are renamed bel ( a ) (for bel) and bel ( b ) (for bsl). The wild-type Bel gene encodes a novel cytochrome P450 monooxgenase, named CYP81A6. Analysis of the mutant protein sequence also revealed the reason for bel ( a ) being slightly tolerant than bel ( b ). Introduction of the wild-type Bel gene rescued the bentazon- and sulfonylurea-sensitive phenotype of bel ( a ) mutant. On the other hand, expression of antisense Bel in W6154S induced a mutant phenotype. Based on these results we conclude that the novel cytochrome P450 monooxygenase CYP81A6 encoded by Bel confers resistance to two different classes of herbicides.

Recently, directional modulation has become an active research area in wireless communications due to its security. Unlike existing research work, we consider a multi-beam directional modulation (MBDM) scenario with imperfect desired direction knowledge. In such a setting, a robust synthesis scheme is proposed for MBDM in broadcasting systems. In order to implement the secure transmission of a confidential message, the beamforming vector of the confidential message is designed to preserve its power as possible in the desired directions by minimizing its leakage to the eavesdropper directions while the projection matrix of artificial noise (AN) is to minimize the effect on the desired directions and force AN to the eavesdropper directions by maximizing the average receive signal-toartificial-noise ratio at desired receivers. Simulation results show that compared with conventional methods, the proposed robust scheme achieves much better bit error rate performance along desired directions for a given signal-to-noise ratio (SNR). From the secrecy-rate aspect, the proposed scheme performs better than conventional methods for almost all SNR regions. In particular, in the medium and high SNR regions, the rate improvement of the proposed scheme over conventional methods is significant.

In this paper, a practical wireless transmission scheme is proposed to transmit confidential messages to the desired user securely and precisely by the joint use of multiple techniques including artificial noise (AN) projection, phase alignment (PA)/beamforming, and random subcarrier selection (RSCS) based on OFDM, and directional modulation (DM), namely RSCS-OFDM-DM. This RSCS-OFDM-DM scheme provides an extremely low-complexity structures for the transmitter and desired receiver and makes the secure and precise wireless transmission realizable in practice. For illegal eavesdroppers, the receive power of confidential messages is so weak that their receivers cannot intercept these confidential messages successfully once it is corrupted by AN. In such a scheme, the design of phase alignment/beamforming vector and AN projection matrix depend intimately on the desired direction angle and distance. It is particularly noted that the use of RSCS leads to a significant outcome that the receive power of confidential messages mainly concentrates on the small neighboring region around the desired receiver and only small fraction of its power leaks out to the remaining large broad regions. This concept is called secure precise transmission. The probability density function of real-time receive signal-to-interference-and-noise ratio (SINR) is derived. Also, the average SINR and its tight upper bound are attained. The approximate closed-form expression for average secrecy rate is derived by analyzing the first-null positions of SINR and clarifying the wiretap region. From simulation and analysis, it follows that the proposed scheme actually can achieve a secure and precise wireless transmission of confidential messages in lineof-propagation channel, and the derived theoretical formula of average secrecy rate is verified to coincide with the exact one well for medium and large scale transmit antenna array or in the low and medium SNR regions.

This strain of guinea pigs has spontaneous axial refractive errors that may be genetically or epigenetically determined. Interestingly, it differs from other published strains that show no refractive errors, vivid accommodation, or pupil responses.

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