桔小实蝇雄成虫的空间分布格局

用多种聚集度指标分析了桔小实蝇Bactrocera(Bactrocera)dorsalis(Hendel)雄成虫在番石榴和杨桃园的空间分布格局．结果表明,该虫雄成虫分布基本成分为个体群,雄虫个体间相互排斥,其密度高低影响空间分布,密度高时呈随机分布,密度低时主要是随机分布,部分为聚集分布．     

Natural Products from Antarctic Colonial Ascidians of the Genera Aplidium and Synoicum: Variability and Defensive Role

Ascidians have developed multiple defensive strategies mostly related to physical, nutritional or chemical properties of the tunic. One of such is chemical defense based on secondary metabolites. We analyzed a series of colonial Antarctic ascidians from deep-water collections belonging to the genera Aplidium and Synoicum to evaluate the incidence of organic deterrents and their variability. The ether fractions from 15 samples including specimens of the species A. falklandicum, A. fuegiense, A. meridianum, A. millari and S. adareanum were subjected to feeding assays towards two relevant sympatric predators: the starfish Odontaster validus, and the amphipod Cheirimedon femoratus. All samples revealed repellency. Nonetheless, some colonies concentrated defensive chemicals in internal body-regions rather than in the tunic. Four ascidian-derived meroterpenoids, rossinones B and the three derivatives 2,3-epoxy-rossinone B, 3-epi-rossinone B, 5,6-epoxy-rossinone B, and the indole alkaloids meridianins A–G, along with other minoritary meridianin compounds were isolated from several samples. Some purified metabolites were tested in feeding assays exhibiting potent unpalatabilities, thus revealing their role in predation avoidance. Ascidian extracts and purified compound-fractions were further assessed in antibacterial tests against a marine Antarctic bacterium. Only the meridianins showed inhibition activity, demonstrating a multifunctional defensive role. According to their occurrence in nature and within our colonial specimens, the possible origin of both types of metabolites is discussed.     

基于机器视觉的八角颜色与果形识别研究

为了提高八角外观检测精度及效率，基于机器视觉技术对不同果形和颜色的八角进行识别和处理。果形在RGB、HSI颜色空间中，根据棕红、黑红、褐红在H颜色空间的区别，提取了不同颜色的八角H分量值，识别正确率为95.12%、95.12%、97.56%。利用极坐标变换思想建立极坐标模型，通过对极坐标模型错位相减、归一化、角数判别，有效的识别八角的角数，识别正确率为94.73%；在角数识别的基础上通过余弦定理实现了粗短八角角瓣、瘦长八角角瓣的判别，识别正确率分别为94.29%、97.14%；通过对极坐标变换后的轮廓进行傅里叶变换识别了粗短八角角瓣和瘦长八角角瓣，识别正确率分别为94.29%、94.29%；通过对八角波峰点进行标准差分析，有效地识别了八角是否均匀。以上方法识别率高且精确，为八角的外观检测技术提供了理论基础和前景。