庙岛群岛海域斑海豹的分布与保护

庙岛群岛是斑海豹的重要栖息地,2002年和2004年对该处进行了调查。结果表明:庙岛群岛的海洋环境条件比较适合斑海豹的生存;2002年和2004年3～5月,在庙岛群岛主要观察区域斑海豹的数量分别为72和87头,年变化不大。从时间分布来看:每年的3月初即发现斑海豹,3月下旬～4月初斑海豹数量最多,4月下旬开始有斑海豹陆续离开,5月中旬基本上完全离开。综合历史资料和调查结果对斑海豹在庙岛群岛的空间分布进行了介绍。     

A lysimeter experiment to investigate the effect of surface sealing on hydrology and pesticide loss from the reconstructed profile of a clay soil. 1. Hydrological characteristics

Abstract. A laboratory experiment was designed to assess the impact of surface seal development on the hydrological response of a clay soil. The influence of surface sealing on vertical macropore flow and lateral throughflow was of particular interest. The extent and development of the surface seal in repacked lysimeters was designed to match that recorded over two growing seasons at a clay field site in Essex, and was not extensive enough to reduce significantly the infiltration capacity of the soil. Consequently, the hydrological response of the lysimeters was similar under sealed and unsealed conditions, with a more rapid wetting response under sealed conditions being attributed to the higher soil moisture content required to create the surface seal. Macropore flow was initiated at the A/B soil boundary of the lysimeters, in response to the development of a saturated layer. The rate of macropore and throughflow in the soil was dictated by rainfall intensity at the soil surface as this controlled the depth of water in the perched water table. Simulation of the tensiometer response in the lysimeters demonstrated that it was possible to attribute the rapid movement of water through the A horizon to water displacement processes alone, without recourse to preferential flow processes.     

封堵性魔芋凝胶的研制与评价

采用高盐度魔芋粉水溶胶与胶凝剂作用,在加热条件下胶凝,形成具有一定强度的弹性凝胶。溶胶浓度和胶凝剂浓度越高,胶凝时间越短;在室温至70℃范围内,温度越高,胶凝时间越短。该凝胶具有生物降解性,加入杀菌剂后凝胶性能不变,但能够在室温下稳定存在2年以上。人造岩心的封堵实验证明,该凝胶封堵压力可达7MPa以上,可以作为油井堵水剂使用。     

Apparent Seroprevalence of Salmonella spp. in Harp Seals in the Greenland Sea as Determined by Enzyme-linked Immunosorbent Assay

An indirect ELISA was developed as a possible tool for surveillance of the seroprevalence of Salmonella spp. in harp seals. This species is hunted for human consumption and thus transmission of disease to humans cannot be excluded. To cover a broad spectrum of serogroups, a mixture of the lipopolysaccharides (LPS) of S. typhimurium and S. choleraesuis was used as the antigen in this pilot study. Chicken anti-harp-seal immunoglobulin horseradish peroxidase conjugate served as the immunoconjugate. Sera from four captive harp seals, which were Salmonella culture-negative and had no clinical or historical evidence of salmonellosis, were used as negative controls. After immunization with an inactivated S. typhimurium vaccine, further sera from these seals were used as positive controls, as no serum from naturally infected animals was available. Serum samples from 93 harp seals caught in the Greenland sea in 1999 were examined, and anti-Salmonella antibodies were found in the samples from two individuals (seroprevalence 2.2%). Although Salmonella has been isolated from other pinniped species, this is the first documentation of Salmonella-seropositive harp seals. This study contributes to the evaluation of the importance of salmonellosis in arctic marine mammals and thus to the prevention of potential outbreaks of this important zoonosis.     

Analysis of blood gases,serum fat and serum protein: a new approach to estimate survival chances of stranded Harbor seal (Phoca vitulina) pups from the German North Sea

Background

Facing numerous challenges, such as illness, storms or human disturbance, some harbor seal (Phoca vitulina) pups lose contact to their dams and are found abandoned along the North Sea coast. In Schleswig-Holstein, pups with the prospect of surviving rehabilitation are admitted to the Seal Center Friedrichskoog. Despite elaborate clinical health assessments on admission, including differential hematology, in 2010, 17% of 108 admitted pups did not survive the first 20 days. The death rate during the years 2006 and 2009 varied between 9 and 19%. To broaden the spectrum of variables which could be predictive for survival, blood gas and serum analyses were performed for 99 pups using venous blood. Variables included total CO₂, pH, partial CO₂, HCO₃^–, base excess and anion gap as well as glucose, urea nitrogen, sodium, potassium and chloride. Moreover, total serum protein and fat (triglyceride) concentrations were measured for all pups on admission.

Results

Repeated measurements of 12 randomly selected individuals revealed a significant (p = 0.002) positive influence of time in rehabilitation on triglyceride concentrations. This trend probably shows the improvement of the pups’ nutritional status as a consequence of the shift from milk replacer formula to fish. No such positive influence was detected for total protein concentrations though. Hematologic values, including blood gases, were not predictive for survival.

Conclusions

For the first time blood gas values are reported in this study for a large sample size (N = 99) of seal pups (regardless of their health status). The ranges and medians calculated from the data can serve as a stepping stone towards the establishment of reference values for neonate harbor seals. However, future investigations on the development of blood gases in harbor seals with different health conditions and ages over time are necessary to allow for a better understanding of acid–base regulation in harbor seals.     

Serengeti III: Human Impacts on Ecosystem Dynamics

During a survey of seals in September and October 2009 at Gough Island, South Atlantic Ocean, we recorded goose barnacles (Lepas australis) attached to the pelage of two of the 12 elephant seals (Mirounga leonina) inspected and one of the seven vagrant Antarctic fur seals (Arctocephalus gazella) which were found amongst the resident Subantarctic fur seals (A. tropicalis). We also recorded a goose barnacle attached to a Northern rockhopper penguin (Eudyptes chrysocome moseleyi).     

组培封口材料透气率的测定与计算

组培容器封口材料的透气率对组培微环境和组培苗具有重要影响。它是合理评价和正确选用封口材料的重要依据,也是组培微环境间接自动化和精准化调控的基础数据。该研究针对国外关于透气率算法和测定研究中的问题,依据严密数学过程和数理统计原理研究并建立透气率算法,研制与算法相适应的测量装置和测量方法,测定并计算了透气纸、4层硫酸纸和低密度聚乙烯膜的透气率,分别为1.551次·h^-1,0.408次·h^-1和0.302次·h^-1。     

静压干气密封端面流场数值模拟

为了提高静压干气密封的性能,基于N-S方程、层流模型、SIMPLEC算法,在节流孔直径和端面间隙变化的情况下,对静压干气密封流场进行数值模拟,重点考察了端面气膜压力及开启力的变化情况.数值结果表明：密封气在流经节流孔后形成显著的压力降,该压力降的大小会随端面间隙增大而增大,随节流孔径增大而减小.端面压力在均压浅槽区中心附近最高,向四周逐渐下降,在均压浅槽区边沿附近,压力梯度较大.开启力总体随间隙增大而减小,极小值接近于0.当端面间隙在5～12μm范围内,开启力随间隙增大而迅速减小,端面气膜具有很大的刚度.较小的节流孔直径可在小端面间隙条件下获得更大的气膜刚度.根据计算数据,对某轴径为30mm的反应釜搅拌器轴端密封,在转速为50～300 r/min范围内成功进行了台架实验,重点对泄漏量和端面磨损状况进行了监测,结果表明密封实现了稳定的非接触式运转.     

对喷雾机卸压系统的改进设计

本文针对现有喷雾机存在皮碗容易损坏、易跳闸熄火的原因进行了分析，提出了用液压控制自动卸压装置取代原手动机控卸压的设想．并对此自动卸压装置的工作原理及设计计算进行了探讨．证明此改进设计可行，可以应用于生产实践．     

底表面粗糙度影响干气密封性能的确定性方法

为了研究槽底表面粗糙度对干气密封性能的影响,建立沿密封端面径向分布为正弦曲线的槽底表面粗糙度模型,考察在单个取样长度Lr内正弦波波长λ对密封性能的影响,确定了正弦波波数n=10,即波长λ=0.08 μm,采用近似解析法求解密封端面间隙的气膜压力分布,得到了不同槽深和不同膜厚下槽底表面粗糙度对干气密封端面开启力和泄漏率的影响规律.结果表明:针对所研究的工况,与光滑面相比,槽底面粗糙度Ra=0.4 μm时,开启力的最大相对误差(绝对值)为0.12%,泄漏率的最大相对误差(绝对值)0.31%;槽底表面粗糙度Ra=0.8 μm时,开启力的最大相对误差(绝对值)为0.50%,泄漏率的最大相对误差(绝对值)1.26%.这说明,一般工况下,槽底表面粗糙度Ra≤0.8 μm时,可忽略槽底表面粗糙度对干气密封性能的影响.而在非槽区气膜厚度h₀<2 μm的运行工况下,建议将槽底表面粗糙度Ra降低到0.4 μm以下.