A theory of circular organization and negative feedback: defining life in a cybernetic context

All life today incorporates a variety of systems controlled by negative feedback loops and sometimes amplified by positive feedback loops. The first forms of life necessarily also required primitive versions of feedback, yet surprisingly little emphasis has been given to the question of how feedback emerged out of primarily chemical systems. One chemical system has been established that spontaneously develops autocatalytic feedback, the Belousov-Zhabotinsky (BZ) reaction. In this essay, I discuss the BZ reaction as a possible model for similar reactions that could have occurred under prebiotic Earth conditions. The main point is that the metabolism of contemporary life evolved from primitive homeostatic networks regulated by negative feedback. Because life could not exist in their absence, feedback loops should be included in definitions of life.     

Biological potential of Martian hydrothermal systems

A source of energy to power metabolism may be a limiting factor in the abundance and spatial distribution of past or extant life on Mars. Although a global average of chemical energy available for microbial metabolism and biomass production on Mars has been estimated previously, issues of how the energy is distributed and which particular environments have the greatest potential to support life remain unresolved. We address these issues using geochemical models to evaluate the amounts of chemical energy available in one potential biological environment, Martian hydrothermal systems. In these models, host rock compositions are based upon the compositions of Martian meteorites, which are reacted at high temperature with one of three groundwater compositions. For each model, the values for Gibbs energy of reactions that are important for terrestrial chemosynthetic organisms and likely representative for putative Martian microbes are calculated. Our results indicate that substantial amounts of chemical energy may be available in these systems, depending most sensitively upon the composition of the host rock. From the standpoint of sources of metabolic energy, it is likely that suitable environments exist to support Martian life.     

Biosignatures of early earths

A major goal of NASA's Origins Program is to find habitable planets around other stars and determine which might harbor life. Determining whether or not an extrasolar planet harbors life requires an understanding of what spectral features (i.e., biosignatures) might result from life's presence. Consideration of potential biosignatures has tended to focus on spectral features of gases in Earth's modern atmosphere, particularly ozone, the photolytic product of biogenically produced molecular oxygen. But life existed on Earth for about 1(1/2) billion years before the buildup of atmospheric oxygen. Inferred characteristics of Earth's earliest biosphere and studies of modern microbial ecosystems that share some of those characteristics suggest that organosulfur compounds, particularly methanethiol (CH(3)SH, the sulfur analog of methanol), may have been biogenic products on early Earth. Similar production could take place on extrasolar Earth-like planets whose biota share functional chemical characteristics with Earth life. Since methanethiol and related organosulfur compounds (as well as carbon dioxide) absorb at wavelengths near or overlapping the 9.6-microm band of ozone, there is potential ambiguity in interpreting a feature around this wavelength in an extrasolar planet spectrum.     

一种基于卫星节点的时变拓扑网络模型

卫星网络与地面固定网络有着本质的差别,特别是它的时变特性,使得成熟的固定拓扑网络理论不能很好地应用到卫星网络中。将卫星网络抽象为以时间为变量的周期函数矩阵,并引入图论,提出一种基于卫星节点的时变拓扑网络模型,讨论模型中节点间的关系和模型离散化条件,给出该模型的离散化形式以及离散时间序列选取原则和相应的证明和仿真,最后指出现有的虚拟节点、有限状态自动机、快照系列、动态虚拟拓扑等研究卫星网络的方法都可以纳入所提出的模型框架中。     

聚氨酯推进剂化学交联网络模型及c的计算

所谓复杂化学文联型聚氨酯网络是指固化体系中含有官能度大于4的预聚物及固化剂固化形成的交联网络。本文研究分析了复杂化学文联型聚氨酯（PU）网络形成过程和网络结构的特点，建立了复杂网络结构的简化模型，提出了计算其的理论公式。这些公式在PU弹性体及PU推进剂结构与性能之间关系的研究和PU泡沫、弹性体、PU固体推进剂等制品的质量控制中，将有广泛的应用。     

Energy cycling and hypothetical organisms in Europa's ocean

While Europa has emerged as a leading candidate for harboring extraterrestrial life, the apparent lack of a source of free energy for sustaining living systems has been argued. In this theoretical analysis, we have quantified the amount of energy that could in principle be obtained from chemical cycling, heat, osmotic gradients, kinetic motion, magnetic fields, and gravity in Europa's subsurface ocean. Using reasonable assumptions based on known organisms on Earth, our calculations suggest that chemical oxidation-reduction cycles in Europa's subsurface ocean could support life. Osmotic and thermal gradients, as well as the kinetic energy of convection currents, also represent plausible alternative sources of energy for living systems at Europa. Organisms thriving on these gradients could interact with each other to form the complex energy cycling necessary for establishing a stable ecosystem.     

国外载人航天的生命保障系统

文章简要介绍了载人航天3种生命保障方式的一些特点,重点介绍了基于物理/化学方法的部分物质再生生命保障系统和生物生态闭环生命保障系统两种方式的再生技术,并例举了ESA的生命保障发展计划,即生物空气过滤技术计划和微生态生命保障系统方案计划.     

Influence of ionic inorganic solutes on self-assembly and polymerization processes related to early forms of life: implications for a prebiotic aqueous medium

A commonly accepted view is that life began in a marine environment, which would imply the presence of inorganic ions such as Na+, Cl-, Mg2+, Ca2+, and Fe2+. We have investigated two processes relevant to the origin of life--membrane self-assembly and RNA polymerization--and established that both are adversely affected by ionic solute concentrations much lower than those of contemporary oceans. In particular, monocarboxylic acid vesicles, which are plausible models of primitive membrane systems, are completely disrupted by low concentrations of divalent cations, such as magnesium and calcium, and by high sodium chloride concentrations as well. Similarly, a nonenzymatic, nontemplated polymerization of activated RNA monomers in ice/eutectic phases (in a solution of low initial ionic strength) yields oligomers with > 80% of the original monomers incorporated, but polymerization in initially higher ionic strength aqueous solutions is markedly inhibited. These observations suggest that cellular life may not have begun in a marine environment because the abundance of ionic inorganic solutes would have significantly inhibited the chemical and physical processes that lead to self-assembly of more complex molecular systems.     

Long-duration space mission regenerative life support.

The paper deals with the construction of physical/chemical life support systems of orbiting space station Mir and the Russian segment of the international space station (ISS). Based on experience gained in development and long-term operation of systems for water recovery and air revitalization balance and energy/mass characteristics of promising life support systems (LSS) are analyzed. Physical/chemical life support systems with regenerative systems updated as a result of the operation on the ISS may be used at an initial phase of manned interplanetary missions.     

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.     

基于小波神经网络的双足步行机器人步态规划控制器

对于传统的神经网络中神经元模型在结构和信息存储能力上存在的不足，本文提出了一种基于广义小波其函数网络的神经元集聚模型，这种小波神经网络不仅收敛速度快，非线性逼近能力更好，而且具有内部结构变尺度、自适应调整和广义信息存储等智能化特点，更符合生物原型的实际情况。静态学习和准动态学习仿真实验证明这种神经网络结构的有效性。     

Hyper-interspersed nano/MEMS-architecture design for new concepts in miniature robotics for space exploration

Launch weight and volume requirements are substantially decreased by reduction of probe size in exploration mission systems, as mass and volume both scale as the third power of system size. Accordingly, the already quite developed MEMS (Micro Electro Mechanical System) technology, that offers low cost, small, light weight, and increasingly reliable devices through durability and redundancy, is strongly attractive as a near-term technology for significantly reducing the cost to launch and operate space systems. It is shown that the final goal of MEMS technology, i.e. the merging through solid state microdcvices of the functions of sensing, computation, communication and actuation, can lead to a new, biomimetic kind of miniature robotics, particularly suitable for planetary exploration, through molecular mono- electronics/MEMS integration jointly with a hyper-interspersed architecture made up of autonomous units embodying sensors, information processors and actuators. The problem tackled here concerns the basic design of such miniature robots, from some μm to insect size, featuring finely structured intelligent autonomous parts as smart skins, sensory and manipulating members working on the analogue external reality and communicating with their inner molecular level nondiscrete pseudo-analogue information processing networks. The (mesoscopic network)/MEMS units are shown to embody a quantum mechanical/macroscopic world connection, in which the nondiscrete molecular devices allow the automaton parts to perform very complex, fast information processing operations as metaphores of bionic functions like learning, attention, and decision making under uncertain conditions, this last due to the stochasticity inherent in the quantum network. Flexible architectures instead of von Neumann type rigid architectures in addition to hyper-interspersion of autonomous units can be realized through such nano/MEMS devices, and the μm — cm size of the whole robots and their organs allow dynamic biochemical, possibly reaction - diffusion, spatially separated highly nonlinear systems to be exploited as additional primitive computing devices (e.g. chemical oscillators, dissipative biomolecular distributed systems, planar photoactivated enzyme biosensors). Each interspersed unit can be designed as a multilevel nondiscrete system according to the information processing “rank” to be obtained in simulating the biological nervous system activity.     

A combinatorial approach to biochemical space: description and application to the redox distribution of metabolism

Redox chemistry is central to life on Earth. It is well known that life uses redox chemistry to capture energy from environmental chemical energy gradients. Here, we propose that a second use of redox chemistry, related to building biomass from environmental carbon, is equally important to life. We apply a method based on chemical structure to evaluate the redox range of different groups of terrestrial biochemicals, and find that they are consistently of intermediate redox range. We hypothesize the common intermediate range is related to the chemical space required for the selection of a consistent set of metabolites. We apply a computational method to show that the redox range of the chemical space shows the same restricted redox range as the biochemicals that are selected from that space. By contrast, the carbon from which life is composed is available in the environment only as fully oxidized or reduced species. We therefore argue that redox chemistry is essential to life for assembling biochemicals for biomass building. This biomass-building reason for life to require redox chemistry is in addition (and in contrast) to life's use of redox chemistry to capture energy. Life's use of redox chemistry for biomass capture will generate chemical by-products-that is, biosignature gases-that are not in redox equilibrium with life's environment. These potential biosignature gases may differ from energy-capture redox biosignatures.     

空间仿生可变构智能感知网络技术

基于仿生集群系统感知功能与行为的视角，提出了空间感知网络的若干前沿科学问题，包括仿生可变构异构空间分布式智能感知网络设计、单星自主机动对准和协调操控、星群协同相对测量与控制等。在干扰对抗态势下，空间感知网络的生存智能需求是保持各节点的可变构型网络、异构分布式感知与协调控制，从抗扰、容错和节能等角度提出了未来智能感知网络所应具有的安全、绿色和免疫等特征。仿生空间感知网络的目标是通过可变构异构分布式星群设计，实现星群多源信息融合和“眼、耳、脑、体、群”的智能协调，提高感知网络的智能协调能力以及对于空地目标与空间态势的感知、理解、预判和机动处置能力。     

基于亲和传播算法的车辆自组织网络分簇组网方法

随着5G通信和自动驾驶汽车的发展，车辆自组织网络VANET（Vehicular Ad Hoc Network）作为一种新型的移动自组织网络，因其在改善道路安全、为驾驶员和乘客提供便利方面的潜力，而引起学术界和工业界的广泛关注。它可以通过提供交通流量、事故通知、危险警告、可能存在的定位偏差、天气等信息来增强道路安全，从而提高交通效率。由于车辆的高速移动会经常引起网络拓扑中断，因此一个设计良好的路由协议至关重要。提出了一种适用于车辆自组织网络环境的基于分簇的路由协议，设计并实现了一种基于亲和传播算法的分簇组网模型V-APC（VANET-Affinity Propagation Clustering）。通过重新定义亲和传播算法的相似函数，设计了簇头的选择过程、簇的形成过程还有簇的维护过程。结果表明：采用上述方法形成的簇，在簇内的通信性能和簇稳定性方面具有显著优势，使得该协议在路由延迟和数据包转发成功率方面表现优异。     

Supraglacial sulfur springs and associated biological activity in the Canadian high arctic-signs of life beneath the ice

Unique springs, discharging from the surface of an arctic glacier, release H(2)S and deposit native sulfur, gypsum, and calcite. The presence of sulfur in three oxidation states indicates a complex series of redox reactions. Physical and chemical conditions of the spring water and surrounding environment, as well as mineralogical and isotopic signatures, suggest biologically mediated reactions. Cell counts and DNA analyses confirm bacteria are present in the spring system, and a limited number of sequenced isolates suggests that complex communities of bacteria live within the glacial system.     

有烧蚀气体产物影响的化学非平衡粘性流数值计算研究

本文是针对高超声速绕流钝锥体再入飞行器，研究有烧蚀气体产物影响的化学非平衡反应粘性流ＮＳ方程数值计算方法。通过带有化学源项的ＮＳ方程对流动作数值模拟，总的连续方程由单个组元守恒方程组代替。对１３个化学组元，２６个气相化学反应，以及２个气相－固相化学反应，研究烧烛碳－空气的化学反应系统，并与纯空气化学反应系统的计算结果进行比较。利用二阶迎风ＴＶＤ差分格式和激波捕捉法，计算球锥体头部和身部化学非平衡粘性流场     

Information theory,animal communication,and the search for extraterrestrial intelligence

We present ongoing research in the application of information theory to animal communication systems with the goal of developing additional detectors and estimators for possible extraterrestrial intelligent signals. Regardless of the species, for intelligence (i.e., complex knowledge) to be transmitted certain rules of information theory must still be obeyed. We demonstrate some preliminary results of applying information theory to socially complex marine mammal species (bottlenose dolphins and humpback whales) as well as arboreal squirrel monkeys, because they almost exclusively rely on vocal signals for their communications, producing signals which can be readily characterized by signal analysis. Metrics such as Zipf's Law and higher-order information-entropic structure are emerging as indicators of the communicative complexity characteristic of an “intelligent message” content within these animals’ signals, perhaps not surprising given these species’ social complexity. In addition to human languages, for comparison we also apply these metrics to pulsar signals—perhaps (arguably) the most “organized” of stellar systems—as an example of astrophysical systems that would have to be distinguished from an extraterrestrial intelligence message by such information theoretic filters. We also look at a message transmitted from Earth (Arecibo Observatory) that contains a lot of meaning but little information in the mathematical sense we define it here. We conclude that the study of non-human communication systems on our own planet can make a valuable contribution to the detection of extraterrestrial intelligence by providing quantitative general measures of communicative complexity. Studying the complex communication systems of other intelligent species on our own planet may also be one of the best ways to deprovincialize our thinking about extraterrestrial communication systems in general.     

H2／O2燃烧的超声速非平衡流动的数值模拟

本文从包含组分方程的完全ＮＳ方程出发，采用ＮＮＤ格式和Ｈ２／Ｏ２燃烧模型，通过求解ＮＳ方程，模拟了具有压缩拐角的二维管道和球头两类激波点火、燃烧流动。计算清楚地给出了流场中的激波，爆震波以及各种物理量的分布，并分析了激波、爆震波及其相互之间的合。在此基础上，讨论了稀释剂添加情况对流场的影响。计算中为了解决耦合方程组的刚性，提高计算的稳定时间步长，对化学生成源项，妥善地采用了隐式处理技术。