The sugarcane borer, Diatraea saccharalis （E）, is a major maize borer pest and a target of transgenic maize expressing Bacillus thuringiensis （Bt） proteins in South America and the mid-southern region of the Unite...The sugarcane borer, Diatraea saccharalis （E）, is a major maize borer pest and a target of transgenic maize expressing Bacillus thuringiensis （Bt） proteins in South America and the mid-southern region of the United States. Evolution of resistance in target pest populations is a great threat to the long-term efficacy of Bt crops. In this study, we compared the genetic basis of resistance to CrylAb protein in 3 resistant colonies of sugarcane borer established from field populations in Louisiana, USA. Responses of larvae to the CrylAb protein for the parental and 10 other cross colonies were assayed in a diet-incorporated bioassay. All 3 resistant colonies were highly resistant to the CrylAb protein with a resistance ratio of 〉 5 5 5.6 fold. No maternal effect or sex linkage was evident for the resistance in the 3 colonies; and the resistance was functionally nonrecessive at the CrylAb concentrations of 〈 3.16 μg/g, but it became recessive at 〉10μg/g. In an interstrain complementation test for allelism, the Fl progeny from crosses between any 2 of the 3 resistant colonies exhibited the similar resistance levels as their parental colonies, indicating that the 3 colonies most likely shared a locus of CrylAb resistance. Results generated from this study should provide useful information in developing effective strategies for managing Bt resistance in the insect.展开更多
We consider a model of the exploitative competition of two micro-organisms for two complementary nutrients in a chemostat and take into account the interspecific interac- tion. The growth functions occurring in the mo...We consider a model of the exploitative competition of two micro-organisms for two complementary nutrients in a chemostat and take into account the interspecific interac- tion. The growth functions occurring in the model are of general type and the interaction functions are monotonic and positive. By the mean of the Thieme-Zhao theorem, we establish conditions for uniform persistence of the model.展开更多
Bit-interleaved coded modulation (BICM) is suitable to bandwidth-efficient communication systems. Hybrid automatic repeat request (HARQ) can provide more reliability to high-speed wireless data transmission. A new pat...Bit-interleaved coded modulation (BICM) is suitable to bandwidth-efficient communication systems. Hybrid automatic repeat request (HARQ) can provide more reliability to high-speed wireless data transmission. A new path weight complementary convolutional (PWCC) code used in the type-Ⅱ BICM-HARQ system is proposed. The PWCC code is composed of the original code and the complimentary code. The path in trellis with large hamming weight of the complimentary code is designed to compensate for the path in trellis with small hamming weight of the original code. Hence, both of the original code and the complimentary code can achieve the performance of the good code criterion of corresponding code rate. The throughput efficiency of the BICM-HARQ system wit PWCC code is higher than repeat code system, a little higher than puncture code system in low signal-to-noise ratio (SNR) values and much higher than puncture code system, the same as repeat code system in high SNR values. These results are confirmed by the simulation.展开更多
文摘The sugarcane borer, Diatraea saccharalis （E）, is a major maize borer pest and a target of transgenic maize expressing Bacillus thuringiensis （Bt） proteins in South America and the mid-southern region of the United States. Evolution of resistance in target pest populations is a great threat to the long-term efficacy of Bt crops. In this study, we compared the genetic basis of resistance to CrylAb protein in 3 resistant colonies of sugarcane borer established from field populations in Louisiana, USA. Responses of larvae to the CrylAb protein for the parental and 10 other cross colonies were assayed in a diet-incorporated bioassay. All 3 resistant colonies were highly resistant to the CrylAb protein with a resistance ratio of 〉 5 5 5.6 fold. No maternal effect or sex linkage was evident for the resistance in the 3 colonies; and the resistance was functionally nonrecessive at the CrylAb concentrations of 〈 3.16 μg/g, but it became recessive at 〉10μg/g. In an interstrain complementation test for allelism, the Fl progeny from crosses between any 2 of the 3 resistant colonies exhibited the similar resistance levels as their parental colonies, indicating that the 3 colonies most likely shared a locus of CrylAb resistance. Results generated from this study should provide useful information in developing effective strategies for managing Bt resistance in the insect.
文摘We consider a model of the exploitative competition of two micro-organisms for two complementary nutrients in a chemostat and take into account the interspecific interac- tion. The growth functions occurring in the model are of general type and the interaction functions are monotonic and positive. By the mean of the Thieme-Zhao theorem, we establish conditions for uniform persistence of the model.
基金the National Natural Science Foundation of China(Nos. 60302006 and 60462002)
文摘Bit-interleaved coded modulation (BICM) is suitable to bandwidth-efficient communication systems. Hybrid automatic repeat request (HARQ) can provide more reliability to high-speed wireless data transmission. A new path weight complementary convolutional (PWCC) code used in the type-Ⅱ BICM-HARQ system is proposed. The PWCC code is composed of the original code and the complimentary code. The path in trellis with large hamming weight of the complimentary code is designed to compensate for the path in trellis with small hamming weight of the original code. Hence, both of the original code and the complimentary code can achieve the performance of the good code criterion of corresponding code rate. The throughput efficiency of the BICM-HARQ system wit PWCC code is higher than repeat code system, a little higher than puncture code system in low signal-to-noise ratio (SNR) values and much higher than puncture code system, the same as repeat code system in high SNR values. These results are confirmed by the simulation.
