This paper presents a joint method of Doppler Beam Sharpen (DBS) imaging and Signal Subspace Processing (SSP) to achieve Ground Moving Target Indication(GMTI) for along- track dual-antenna airborne radar. When the err...This paper presents a joint method of Doppler Beam Sharpen (DBS) imaging and Signal Subspace Processing (SSP) to achieve Ground Moving Target Indication(GMTI) for along- track dual-antenna airborne radar. When the error of the two antennas (also refers to channels) changes pulse to pulse, the method SSP is used to precisely calibrate the two antennas’ DBS images, then to detect the ground moving targets in the difference image of the two calibrated images. The method DBS-SSP is proved to offer performance improvement on the actually measured data and simulated data.展开更多
The Iberian wall lizard Podarcis hispanica forms part of a species complex with several morphologically and geneti- cally distinct types and populations, which may or may not be reproductively isolated. We analyzed wh...The Iberian wall lizard Podarcis hispanica forms part of a species complex with several morphologically and geneti- cally distinct types and populations, which may or may not be reproductively isolated. We analyzed whether female mate choice based on males＇ chemical signals may contribute to a current pre-mating reproductive isolation between two distinct populations of P. hispanica from central Spain. We experimentally examined whether females choose to establish territories on areas scent-marked by males of their own population, versus areas marked by males of the other population. Results showed that fe- males did not prefer scent-marks of males from their own population. In contrast, females seemed to attend mostly to among-individual variation in males＇ pheromones that did not differ between populations. Finally, to test for strong premating re- productive isolation, we staged intersexual encounters between males and females. The population of origin of males and females did not affect the probability nor the duration of copulations. We suggest that the different environmental conditions in each population might be selecting for different morphologies and different chemical signals of males that maximize efficiency of communication in each environment. However, females in both populations based mate choice on a similar condition-dependent signal of males. Thus, male signals and female mate choice criteria could be precluding premating reproductive isolation between these phenotypically ＂distinct＂ populations [Current Zoology 59 （2）： 210-220, 2013].展开更多
文摘This paper presents a joint method of Doppler Beam Sharpen (DBS) imaging and Signal Subspace Processing (SSP) to achieve Ground Moving Target Indication(GMTI) for along- track dual-antenna airborne radar. When the error of the two antennas (also refers to channels) changes pulse to pulse, the method SSP is used to precisely calibrate the two antennas’ DBS images, then to detect the ground moving targets in the difference image of the two calibrated images. The method DBS-SSP is proved to offer performance improvement on the actually measured data and simulated data.
文摘The Iberian wall lizard Podarcis hispanica forms part of a species complex with several morphologically and geneti- cally distinct types and populations, which may or may not be reproductively isolated. We analyzed whether female mate choice based on males＇ chemical signals may contribute to a current pre-mating reproductive isolation between two distinct populations of P. hispanica from central Spain. We experimentally examined whether females choose to establish territories on areas scent-marked by males of their own population, versus areas marked by males of the other population. Results showed that fe- males did not prefer scent-marks of males from their own population. In contrast, females seemed to attend mostly to among-individual variation in males＇ pheromones that did not differ between populations. Finally, to test for strong premating re- productive isolation, we staged intersexual encounters between males and females. The population of origin of males and females did not affect the probability nor the duration of copulations. We suggest that the different environmental conditions in each population might be selecting for different morphologies and different chemical signals of males that maximize efficiency of communication in each environment. However, females in both populations based mate choice on a similar condition-dependent signal of males. Thus, male signals and female mate choice criteria could be precluding premating reproductive isolation between these phenotypically ＂distinct＂ populations [Current Zoology 59 （2）： 210-220, 2013].
