Effects of intracoelomic alfaxalone–dexmedetomidine on righting reflex in common garter snakes (Thamnophis sirtalis): preliminary data

ObjectiveTo evaluate the effect of dexmedetomidine on alfaxalone immobilization in snakes.Study designNonblinded, crossover study.AnimalsA total of eight mature common garter snakes (Thamnophis sirtalis).MethodsSnakes were administered each of three treatments intracoelomically: alfaxalone (30 mg kg^–1; treatment A), alfaxalone (30 mg kg^–1) combined with dexmedetomidine (0.05 mg kg^–1; treatment AD0.05); and alfaxalone (30 mg kg^–1) combined with dexmedetomidine (0.10 mg kg^–1; treatment AD0.10). A minimum of 10 days elapsed between experimental trials. Times to loss of righting reflex (LRR) and return of righting reflex (RRR) were recorded. Heart rate (HR) was recorded every 5 minutes throughout the period of LRR and averaged for each snake. Times to LRR and RRR, and mean HR in snakes that achieved LRR were reported.ResultsLRR occurred in eight (100%), five (63%) and three (38%) snakes in treatments A, AD0.05 and AD0.10, respectively. For all treatments, time to LRR ranged 3–20 minutes. Median (range) times to RRR were 39 (30–46), 89 (62–128) and 77 (30–185) minutes for treatments A, AD0.05 and AD0.10, respectively. In animals where righting reflex was lost, mean HR was lower in all dexmedetomidine treatments compared with treatment A.Conclusions and clinical relevanceIn this pilot study, alfaxalone resulted in reliable immobilization, whereas dexmedetomidine and alfaxalone combinations resulted in highly variable durations of immobilization with low HR in immobilized animals. For snakes that achieved LRR, the addition of dexmedetomidine (0.05 mg kg^–1) to alfaxalone appeared to extend the period of immobilization compared with alfaxalone alone.     

转盘式全自动红枣去核机的设计

为解决目前红枣人工去核过程中劳动强度大、工作效率低、卫生条件差、安全隐患多以及加工的产品质量难以控制等问题,设计了一种多工位转盘式全自动红枣去核机。该装置采用电动机输出的动力经减速器减速后带动两个弧面分度凸轮机构同时进行间歇转位运动和提升运动,使转盘的转位及滑板的上下运动相配合,加上新型扶正去核杆的使用,一次性完成红枣的扶正、定位、去核三道工序,完成红枣的去核任务。同时,对全自动红枣去核机的整机结构在Pro/E软件中进行三维实体建模,并且设计加工出了试验装置。结果证明,该装置各部件组装合理,去核效果理想,可以进行后续的物理样机制作。     

Turning in mid‐air allows aphids that flee the plant to avoid reaching the risky ground

When forced to drop from the plant, flightless arboreal insects can avoid reaching the risky ground by maneuvering their body through the air. When wingless pea aphids (Acyrthosiphon pisum) are threatened by natural enemies, they often drop off their host plant while assuming a stereotypic posture that rotates them in mid‐air, aligning them with their feet pointing downwards. This position may increase their chances of re‐clinging onto lower plant parts and avoid facing the dangers on the ground, although its effectiveness in realistic field conditions has not been tested. We performed both laboratory and outdoor experiments, in which we dropped aphids upon host plants to quantify clinging success in plants with different characteristics such as height and leaf size. Live aphids had twofold higher clinging rates than dead ones, indicating that clinging success is indeed affected by the active aerial‐righting of dropping aphids. The ability to cling was positively dependent on the plants' foliage cover as viewed in vertical direction from above. Therefore, we released aphids in commercial alfalfa (Medicago sativa) fields with varying plant heights and foliage cover and induced them to drop. Most (up to 75%) of the aphids avoided reaching the ground in taller plants (65 cm), and 17% in shorter plants (21 cm), demonstrating the efficiency of the aphids' response in averting risks: both those of an approaching enemy on the plant and the plethora of new risks on the ground. Evidently, even in complex field environment, the aerial‐righting mechanism can substantially reduce the possible risks following escape from a predator.     

An Investigation into Behavioural Indicators of Stress in Juvenile Scallops

Recessing and righting behaviour requires a big energetic cost to scallops and if the animals are already weakened by the stress of handling, exposure to air and transport they may find if difficult to carry out these manoeuvres. The objectives of this study were to determine the preferred sediment of scallop (Pecten maximus) spat and to determine the recessing and righting behaviour of spat under a dessication stress. The results showed that the time taken to recess was indirectly proportional to the mean sediment size of the sediment. When using the 'preferred' sediment, recessing and righting speed was indirectly proportional to the degree of exposure to air experienced by the animals. Thus by removing seasonal and size variables we were able to demonstrate a clear relationship between quality and behaviour in juvenile scallops. This test is therefore not only sensitive to changes in spat quality but is also a very quick and simple test to perform.