Enemy release or invasional meltdown? Deer preference for exotic and native trees on Isla Victoria,Argentina

Abstract How interactions between exotic species affect invasion impact is a fundamental issue on both theoretical and applied grounds. Exotics can facilitate establishment and invasion of other exotics (invasional meltdown) or they can restrict them by re‐establishing natural population control (as predicted by the enemy‐release hypothesis). We studied forest invasion on an Argentinean island where 43 species of Pinaceae, including 60% of the world's recorded invasive Pinaceae, were introduced c. 1920 but where few species are colonizing pristine areas. In this area two species of Palearctic deer, natural enemies of most Pinaceae, were introduced 80 years ago. Expecting deer to help to control the exotics, we conducted a cafeteria experiment to assess deer preferences among the two dominant native species (a conifer, Austrocedrus chilensis, and a broadleaf, Nothofagus dombeyi) and two widely introduced exotic tree species (Pseudotsuga menziesii and Pinus ponderosa). Deer browsed much more intensively on native species than on exotic conifers, in terms of number of individuals attacked and degree of browsing. Deer preference for natives could potentially facilitate invasion by exotic pines. However, we hypothesize that the low rates of invasion currently observed can result at least partly from high densities of exotic deer, which, despite their preference for natives, can prevent establishment of both native and exotic trees. Other factors, not mutually exclusive, could produce the observed pattern. Our results underscore the difficulty of predicting how one introduced species will effect impact of another one.     

aAd-p53基因靶向治疗癌性胸腹水的临床效果分析

目的:探讨aAd-p53注射液靶向灌注治疗癌性胸腹水的临床疗效和安全性。方法:选择2012年5月-2014年2月在我院接受治疗的癌性胸腹水患者80例,根据治疗方法的不同,将患者随机分为研究组和对照组,每组40例。研究组患者采用腔内灌注rAd-p53治疗,对照组患者采用表阿霉素灌注治疗,观察并比较两组患者的治疗总有效率、不良反应的发生率及KPS功能评分的变化情况。结果:所有患者均顺利完成灌注治疗,病情获得好转,生存质量得到改善。研究组和对照组的治疗总有效率分别为70%、67.5%,两组比较无显著性差异(P0.05)。两组治疗后KPS评分均显著高于治疗前,且研究组高于对照组,差异具有统计学意义(P0.05)。研究组和对照组不良反应的发生率分别为20%和25%,研究组低于对照组,但两组差异并无统计学意义(P0.05)。结论:rAd-p53注射液靶向灌注治疗是一种治疗癌性胸腹水安全有效的方法,值得临床推广。     

春尺蠖蛹雌雄外部形态特征快速鉴别分析

为依据春尺蠖Apocheima cinerarius Erschoff蛹的形态特征快速、无损、准确鉴别雌雄个体,对其头部、胸部、腹部和体色外部鉴别特征进行了分析,并通过解剖生殖系统验证准确性.结果表明:以春尺蠖蛹的胸部和腹部特征识别雌雄准确率明显高于头部和体色特征,识别率可达100％.首先,雌蛹第8腹节腹板前缘中部具有"Y"型沟,与第7腹节腹板后缘形成倒三角状,而雄蛹无此特征.其次,雌蛹生殖孔与产卵孔连接形成裂缝,两侧平坦无突起,而雄蛹第9腹节腹板中央有一纵裂缝的生殖孔,两侧各有半圆状瘤状突起.最后,雌蛹的胸部背板各节间相对长度均小于雄蛹,而雄蛹中胸背板最宽,其后缘明显向外凸起.因此,春尺蠖蛹胸部或腹部特征可用于快速、准确地鉴别雌雄性别.