Quality enhancement of the abundant under‐valued crustacean,lobster krill (Munida spp.), during its chilled storage

Lobster krill (Munida genus) represents an under‐valued crustacean frequently caught on European fishing banks. In this work, its sensory, microbiological and biochemical qualities were evaluated during chilled storage. Additionally, the effects of a prestorage antimelanosic treatment consisting of soaking in sodium metabisulphite (SMB) solutions at two different concentrations (0.25% and 0.75%) were also studied. SMB prestorage treatment provided lobster specimens that still exhibited acceptable sensory quality after 10 days of storage, while control specimens were unacceptable at that time. SMB treatment also resulted in a significant (P < 0.05) inhibition of microbial growth, mainly of Enterobacteriaceae, psychrotrophes and proteolytic bacteria. Low lipid oxidation levels were observed for all batches; however, a significantly higher (P < 0.05) retention of polyunsaturated fatty acids was found in SMB‐treated lobster, especially in the 0.75% SMB batch. The results presented here open the way to the potential commercialisation of currently under‐utilised lobster krill as a chilled product.     

Life under ice in the perennial ice‐covered Lake Glubokoe in Summer (East Antarctica)

This study focuses on hydrological and biotic variables in Lake Glubokoe, which is located in Thala Hills of Enderby Land (East Antarctica). Water and sediment samples and physical measurements were collected once a week in the austral summer (19 December 2010 – 6 February 2011). This lake exhibits perennial ice cover that reached a thickness of 2.5–2.7 m during the study period. A very low concentration of planktonic chlorophyll‐a (0.06–0.45 μg L^?1) was measured in the lake, indicating its ultra‐oligotrophic status. The water was poorly populated by algae and metazoans, especially in upper waters below ice cover to a depth of 2 m. Small planktonic organisms (2–5 μm) were observed throughout the study period, but larger organisms (>8 μm) such as the cyanobacteria Planktolyngbya limnetica occurred only during the warmest period (January). Only few individuals of metazoans (rotifers) were found in planktonic samples. Due to deep light penetration (10–15% of incoming active solar radiation reached the depth of 30 m), thick cyanobacterial mats (30 cm) cover all the bottom surface (grey silts) in the lake. Abundant benthic biota associated with these mats was found (up to 1000 ind. m^?2). Among the benthic metazoans, bdelloid rotifers and tardigrades were the dominating taxa. The results of this study suggest a typical ecological feature of most subglacial lakes in East Antarctica is that metazoans are very poor in the pelagic zone, preferring instead to occupy an area near the lake bottom because of a favourable constant temperature of 4 °C, good level of dissolved oxygen and available food resources as the bacterial detritus.     

Design, analysis and control for an antarctic modular manipulator

Antarctic scientific expedition has important strategic significance. It is an inevitable trend to apply robots to assist researchers during the Antarctic expedition. However, the robot manipula- tors at present have a series of problems and unable to meet the requirements of the Antarctic expe- dition. In this paper, a novel Antarctic modular robot manipulator is proposed, which has a compact structure with modular joints. The robot manipulator has high reliability, and quick assembling-and- disassembling ability. Through well wires arranging and thermal controlling, the manipulator can better adapt to the Antarctic environment. In addition, the work space of the manipulator is serious- ly analyzed, and a new hybrid position/force control method is adopted to make the manipulator per- form better. Simulation results validate the control method and show that the robot manipulator has a good performance to meet the requirements of Antarctic expedition.     

In situ Sea Ice Experiments in McMurdo Sound: Cyclic Loading, Fracture, and Acoustic Emissions

The breakup of first-year sea ice plays an important role in the dynamics and thermodynamics of polar ice covers. A recent research program has studied the in situ mechanical properties of the annual ice in Antarctica to support the development of physically based models of the breakup process. As part of this effort, two field trips were conducted to McMurdo Sound, and the present paper describes the experimental work and presents selected results. The in situ experiments investigated the constitutive and fracture behavior of edge-notched, square plate specimens of first-year ice and involved a detailed characterization of the physical properties and thermal state of the ice. Acoustic emissions, which are generated by microcracking, were monitored in the crack tip vicinity and provide insight regarding the size of the process zone. The paper describes the physical properties and microstructure of the sheet, the cyclic-loading response, and the acoustic emissions activity from an extensive series of experiments conducted on one of the in situ specimens. Varying the cyclic-loading frequency and amplitude provided a means to examine rate effects on the anelastic and viscous components of strain and the extent of microcracking near the crack tip. The viscous deformation rate estimated from the experiments exhibited an increasing power-law exponent with values between one and three. Acoustic emissions monitoring indicated that microcracking occurred in a process zone near the crack tip, and the size of the process zone increased with decreasing cyclic loading frequency. Practical aspects of the experiments are considered, and the results are put into context with the overall modeling goals of the project.     

第二台南极巡天望远镜镜筒的结构设计及模态分析

镜筒是望远镜的基本组成部分,为了能够更好的满足望远镜成像质量的要求,需要对望远镜的镜筒机械结构进行研究。南极巡天望远镜由于其特殊的地理位置及气候、温度条件限制,与普通的望远镜在镜筒上有不同的要求。首先介绍了第二台南极巡天望远镜的光学设计参数及方案,并根据南极的特殊性设计了镜筒的机械结构。其次,通过有限元的分析方法,对望远镜镜筒的等弯沉量、主镜的面形变化进行了分析和计算,使其在工作状态时能满足光学设计的要求,第三,通过模态分析,分析了镜筒的刚度,使其满足电控系统的控制要求,最后通过锤击实验对镜筒的自振频率做了检验检测。经过实验分析,第二台南极巡天望远镜的镜筒能够满足光学的设计要求。     

南极磷虾蛋白营养与功能特性及食用安全性研究进展

南极磷虾富含优质蛋白,被认为是地球上最大、也是最后一个潜在动物性蛋白资源库。目前,南极磷虾蛋白产品以虾粉、冷冻南极磷虾肉等初级产品为主,缺乏高附加值产品。本文系统综述了南极磷虾蛋白的营养特性及其评价、功能特性及其改性、功能活性及其作用机制、食用安全性问题,以期为南极磷虾蛋白的精深加工及综合利用提供研究思路。     

Elemental and mineral characterisation of Coastal Antarctic Aerosols in snow using PIXE and SEM-EDAX

The chemical constituents of snow from a 3 m pit sampled at a coastal Antarctic site were characterised by means of PIXE and SEM-EDAX. Oxygen isotope dating revealed that the pit spanned an 8-year period, from 1986 to 1994. Concentrations measured by PIXE ranged from less than 1 ng g⁻¹ of H₂O for Cu, and Zn to several tens of ng g⁻¹ for Si, S and Cl. The major elements found were Si, S, Al, and Na, which contributed more than 75% of the element loading. Snow layers with elevated Cl concentration were regularly found along the pit. The mineralogy of the insoluble particles determined by SEM-EDAX analyses showed that quartz, plagioclase and clays were the prevalent minerals. The proportion of each element in the insoluble phase was comparable with that previously found in similar studies.     

UV-B辐射对南极冰藻中抗辐射物质的诱导作用

在人工UV－B辐照下培养5种南极冰藻，其中包括三种硅藻：H1硅藻（diatom H1),H2硅藻（diatom H2),H3硅藻（diatom H3)，两种绿藻：L1绿藻（Pyramimonas sp.)，L4绿藻（Chlorophyceae)。研究了UV－B辐射对南极冰藻中抗辐射物质的诱导作用。这些物质被认为具有抵抗UV－B辐射损害而提供保护的作用。结果表明，（1）UV－B辐射诱导产生大量的胞内多糖和胞外多糖物质，胞外多糖附着藻体；（2）UV－B辐射诱导产生新的水溶性色素类物质；（3）UV－B辐射诱导产生新的脂溶性色素类物质，不同种类冰藻产生的新色素的最大吸收峰不同，这些结果使我们初步认识了南极冰藻对南极强辐射环境的适应机理，并为进一步利用UV－B辐射培养南极冰藻产生抗辐射．抗肿瘤、清除自由基等新型活性物质提供依据。