Animal protein production modules in biological life support systems: novel combined aquaculture techniques based on the Closed Equilibrated Biological Aquatic System (C.E.B.A.S.)

Based on the experiences made with the Closed Equilibrated Biological Aquatic System (C.E.B.A.S.) which was primarily deveoloped for long-term and multi-generation experiments with aquatic animals and plants in a space station highly effective fresh water recycling modules were elaborated utilizing a combination of ammonia oxidizing bacteria filters and higher plants. These exhibit a high effectivity to eliminate phosphate and anorganic nitrogen compounds and arc. in addidition. able to contribute to the oxygen supply of the aquatic animals. The C.E.B.A.S. filter system is able to keep a closed artificial aquatic ecosystem containing teleost fishes and water snails biologically stable for several month and to eliminate waste products deriving from degraded dead fishes without a decrease of the oxygen concentration down to less than 3.5 mg/l at 25 °C. More advanced C.E.B.A.S. filter systems, the BIOCURE filters, were also developed for utilization in semiintensive and intensive aquaculture systems for fishes. In fact such combined animal-plant aquaculture systems represent highly effective productions sites for human food if proper plant and fish species are selected The present papers elucidates ways to novel aquaculture systems in which herbivorous fishes are raised by feeding them with plant biomass produced in the BIOCURE filters and presents the scheme of a modification which utilizes a plant species suitable also for human nutrition. Special attention is paid to the benefits of closed aquaculture system modules which may be integrated into bioregenerative life support systems of a higher complexity for, e. g.. lunar or planetary bases including some psychologiccal aspects of the introduction of animal protein production into plant-based life support systems. Moreover, the basic reproductive biological problems of aquatic animal breeding under reduced gravity are explained leading to a disposition of essential research programs in this context.     

Readaptation of the vestibuloocular reflex to 1g-condition in immature lower vertebrates (Xenopus laevis) after micro- or hypergravity exposure

The effects of altered gravitational conditions (AGC) on the development of the static vestibulo-ocular reflex (VOR) and readaptation to 1g were investigated in the amphibian Xenopus laevis. Tadpoles were exposed to microgravity (μg) during the German Space Mission D-2 for 10 days, using the STATEX closed survival system, or to 3g for 9 days during earth-bound experiments. At the beginning of AGC, the tadpoles had not yet developed the static VOR.

The main results were: (i) Tadpoles with ug- or 3g-experience had a lower gain of the static VOR than the 1g-controls during the 2nd and 5th post-AGC days, (ii) Readaptation to response levels of 1g-reared controls usually occurred during the following weeks, except in slowly developing tadpoles with 3g-experience. Readaptation was less pronounced if, during the acute VOR test, tadpoles were rolled from the inclined to the normal posture than in the opposite test situation.

It is postulated that (i) gravity is necessarily involved in the development of the static VOR, but only during a period including the time before onset of the first behavioural response; and (ii) readaptation which is superimposed by the processes of VOR development depends on many factors including the velocity of development, the actual excitation level of the vestibular systems and the neuroplastic properties of its specific pathways.     

Gravity perception and signal transduction in single cells

Cellular signal processing in multi-, as well as in unicellular organisms, has to rely on fundamentally similar mechanisms. Free-living single cells often use the gravity vector for their spatial orientation (gravitaxis) and show distinct gravisensitivities. In this investigation the gravisensitive giant ameboid cell Physarum polycephalum (Myxomycetes, acellular slime molds) is used. Its gravitaxis and the modulation of its intrinsic rhythmic contraction activity by gravity was demonstrated in 180 °turn experiments and in simulated, as well as in actual, near-weightlessness studies (fast-rotating clinostat; Spacelab D1, IML-1). The stimulus perception was addressed in an IML-2 experiment, which provided information on the gravireceptor itself by the determination of the cell's acceleration-sensitivity threshold. Ground-based experiments designed to elucidate the subsequent steps in signal transduction leading to a motor response, suggest that an acceleration stimulus induces changes in the level of second messenger, adenosine 3',5'-cyclic monophosphate (cAMP), indicating also that the acceleration-stimulus signal transduction chain of Physarum uses an ubiquitous second messenger pathway.     

The second generation of the incubator hardware for studying avian embryogenesis under microgravity conditions

This paper describes a technical device, INCUBATOR 1M, which enables incubation of Japanese quail eggs aboard the piloted orbital station.     

非地球同步轨道的应用潜力

最近的一项研究详细论述了在通信业务高峰期,利用非地球同步轨道卫星通信系统所具有的巨大优势。     

用于定常二维跨声速喷管流动分析的N—S解程序

本文介绍了用于分析平面和轴对称定常跨声速喷管流动的有效的Navier—Stokes解算法。本法是利用跳格数值算法在物理上取的坐标中求解守衡型非定常可压缩N—S方程。分析了几种定常跨声速粘性喷管层流,给出了计算结果,并与实验结果进行比较,证实了数值方法的精度和效率。     

固体火箭发动机点火器热通量的测量

使用箔式铂热通量计,对两种几何形状不同的点火器进行瞬间和轴向热通量分布的测量。所用的参数是不同的点火药量,管子长度和喷管喉径。对烟火剂燃烧产生的粒状物质的粒度分布作了研究,并且推论了这种粒子分布对总热量的影响。辐射在总热量传递过程中相对来说是不重要的,而在点火器作用期间,业径发现,由于粒子传热引起的“点”的热通量是热传递的最重要方式之一,事实上,这种传热方式可能是固体火箭发动机中点火火焰最初出现的原因。     

Overview of the Neurolab Spacelab mission

Neurolab is a NASA Spacelab mission with multinational cooperative participation that is dedicated to research on the nervous system. The nervous systems of all animal species have evolved in a one-g environment and are functionally influenced by the presence of gravity. The absence of gravity presents a unique opportunity to gain new insights into basic neurologic functions as well as an enhanced understanding of physiological and behavioral responses mediated by the nervous system. The primary goal of Neurolab is to expand our understanding of how the nervous system develops, functions in, and adapts to microgravity space flight. Twenty-six peer reviewed investigations using human and nonhuman test subjects were assigned to one of eight science discipline teams. Individual and integrated experiments within these teams have been designed to collect a wide range of physiological and behavior data in flight as well as pre- and postflight. Information from these investigations will be applicable to enhancing the well being and performance of future long duration space travelers, will contribute to our understanding of normal and pathological functioning of the nervous system, and may be applied by the medical community to enhance the health of humans on Earth.     

Calcium movement of sarcoplasmic reticulum from hindlimb suspended muscle

The function of the sarcoplasmic reticulum (SR) was examined in the slow soleus and fast extensor digitorum longus (EDL) muscles of rats submitted to 14 days of weightlessness produced by hindlimb suspension (HS). Ca2+ uptake, Ca2+ release and passive Ca2+ leakage through the SR membrane were investigated using a method of caffeine-induced contracture on the single mechanically skinned fibers. In the SR of suspended soleus muscles, the rate of Ca2+ uptake was higher than in the control muscles. However, there was no difference between the suspended and control muscles in the rate of Ca2+ uptake of the SR in EDL after HS. In soleus muscles, Ca2+ movements of the SR from the suspended muscle acquired the properties that were similar to those of the control fast muscle. The study of Ca2+ leakage showed that the velocity and amount of passive Ca2+ leakage from SR in soleus and EDL were apparently increased after HS. The results suggested that the functional properties of the SR membrane in slow and fast muscles were changed after HS.