L'origine géologique des iles des Indes Occidentales en relation avec la dispersion de quelques Malacostracés stygobiontes

The relation between the geological theories andthe origin of the biotas of the West Indian islands is analyzed, mainly based upon observations on the stygobiont fauna of an important number of islands.Two models for the geological origin of theislands have been postulated, viz. an active model (ab novo formation by submarine volcanic action) and a passive model (fragmentation and drift of continental material originating from the protocentral-american region).The same models are encountered in biogeographic considerations on the origin of the biotas of the archipelago. According to the active model (or dispersion model), the biotas arrived from nearby terrestrial regions through dispersion. No doubt this route is, and has been, very important in the West Indies.The passive model (or vicariance model) supposes a passive transport of the biotas «on the back of floating continental fragments. Certain arguments in favour of this model are weighed by the author and are not considered parsimonious. at least for the islands in question.A modification of the passive model is the evolution according to the regission model («stranding of populations of marine origin during periods of marine regression or tectonic uplift); this phenomenon has played an extremely important role in the evolution of limnic biotas, chiefly stygobiont ones, of the Antilles, an island chain that is in a quasi-permanent stage of uplifting.The Bahamas, in the contrary, are in a continuoussubsidence stage. Their limnic faunas do not comprise regression elements, but show clear traces of invasions, probably fairly recent ones, by marine animals.     

2型糖尿病兼抑郁症大鼠模型的建立与评价

目的：用体重检测、空腹血糖检测、宏观表征、旷场实验行为学评价糖尿病兼抑郁症的大鼠模型。方法采用高脂饲料喂养加腹腔注射小剂量链脲佐菌素（ STZ）的方法制备2型糖尿病模型,在其基础上再用21 d慢性束缚的方法建立糖尿病兼抑郁症大鼠模型。将32只Wistar大鼠随机分为3组（ n ＝8）：正常组（N组）,2型糖尿病组（T组）,2型糖尿病兼抑郁症组（T＋D组）。2型糖尿病模型建立后,在慢性束缚的第0、7、14、21天检测大鼠的空腹血糖和体重,并对大鼠的宏观表征、饮食量、粪便、小便、精神状态进行观察,在第21天利用行为学设备分析软件,对大鼠旷场实验进行分析,检测大鼠的抑郁程度,验证评价2型糖尿病兼抑郁症大鼠模型是否成功。结果给予高脂饲料及腹腔注射STZ制备2型糖尿病模型后,T＋D组大鼠的毛发散乱,无光泽,活动迟缓,进食量、饮水量增加,粪便尿量增加,精神萎靡。第0、7、14、21天T组和T＋D组组大鼠体重均下降,与N组比较差异有显著性（P＜0.05;P＜0.01）,21d慢性束缚刺激后,T＋D组体重比T组大鼠体重增加较慢,差异有显著性（P＜0.05）;第0、7、14、21天,T组和T＋D组大鼠血糖均升高,与N组比较差异有显著性（ P＜0.01）,21 d慢性束缚刺激后,第21天T＋D组大鼠血糖比T组较高,差异有显著性（P＜0.01）,大鼠5 min内总移动距离有变化,与N组相比,T组差异没有显著性（P＞0.05）,T＋D组差异有显著性（P＜0.05）;与N组相比,T组大鼠5 min内移动速度减慢,差异有显著性（P＜0.05）,T＋D组差异有显著性（ P＜0.01）。结论利用高脂饲料喂养加腹腔注射小剂量STZ及21天慢性束缚的方法,可以成功复制2型糖尿病兼抑郁症大鼠模型,适用于后续研究。     

Is rotating between static and dynamic work beneficial for our fatigue state?

Shoulder disorders comprise a large part of work-related musculoskeletal disorders. Risk factors, such as repetitiveness and monotony, may cause muscle fatigue and be attenuated by task rotation. We investigated rotation between a dynamic box-lifting task and a relatively static pick-and-place task and aimed to determine whether (1) a high rotation frequency leads to less fatigue development than a low rotation frequency, and (2) a self-selected rotation frequency leads to less fatigue development than imposed rotation frequencies. Ten participants performed four one-hour rotation schedules: two low frequency rotation schedules rotating at 30 min, one high frequency rotation schedule rotating every sixth minute, and a self-selected rotation schedule. Borg, SOFI and electromyography of Trapezius and Deltoid subparts served as fatigue indicators. We found significant signs of fatigue for most schedules regarding the Borg and SOFI ratings and the M. Trapezius pars Descendens. Task rotation frequency had no significant effect on any of the outcome parameters, whereas the self-selected rotation schedule clearly resulted in less development of perceived fatigue than imposed schedules. In conclusion, we think that freedom of rotation has the greatest potential to attenuate potential development of musculoskeletal disorders and we require due caution with the use and interpretation of EMG indicators of fatigue.