Investigating the influence of habitat type and weather conditions on the population dynamics of land snails Vertigo angustior Jeffreys, 1830 and Vertigo moulinsiana (Dupuy, 1849). A case study from western Poland

The conservation of land snails has become an urgent issue because of the current global decline of this group. Detailed knowledge of population dynamics is needed to develop an appropriate strategy for conservation. We investigated the population dynamics of two threatened European land snail species: Vertigo angustior and Vertigo moulinsiana. Although the species may be found at the same site, V. moulinsiana is more tolerant of wetter conditions than is V. angustior. Abundance data for the two species were collected at two sites (one drier and one wetter) in western Poland biweekly during the spring and summer months in 2008 and 2009. In the drier year, snail abundance was similar between the drier and wetter sites. In the wetter year, snail abundances were generally higher than in the dry year, except that the inundation-intolerant V. angustior became less abundant at the wetter site. We conclude that weather affects different species differently and therefore should be considered along with the habitat features in interpreting survey results for land snails.     

单纯发作性眩晕性脑干梗死30例临床和MRI分析

目的　探讨对以发作性眩晕为主的椎 -基底动脉缺血老年患者发作次数、持续时间与脑干梗死的关系。方法　分析 3 0例椎 -基底动脉缺血以发作性眩晕为表现的患者临床特点及磁共振成像 (MRI)表现。结果　患者平均年龄 >60岁 ,6例每日发作 1次 ,每次发作持续时间 >1h,2 4例为每日反复发作≥ 5次 ,每次发作持续 5～2 0 min,无神经系统阳性体征。头颅 MRI检查前全部患者临床诊断为椎 -基底动脉缺血发作 ,头颅 MRI检查后确诊为脑干梗死。结论　对于单纯表现为发作性眩晕 ,特别是年龄 >60岁的患者 ,眩晕每日反复发作≥ 5次或每次持续时间 >1h,要高度怀疑脑干梗死的可能