How Stomaphis aphids use their giant proboscides

To penetrate tree bark, arboreal aphids of the genus Stomaphis Walk. (Hemiptera: Aphididae: Lachninae) have proboscides up to three times their body length. Our observations of S. quercus (L.) complement a recent analysis of the anatomy and function of these mouthparts by clarifying how these relatively short-legged aphids move their proboscides between the resting position, pointing back, and the prognathous working position. The absence of crumenae in Stomaphis aphids and their feeding technique are discussed.     

The ergodic hierarchy, randomness and Hamiltonian chaos

Various processes are often classified as both deterministic and random or chaotic. The main difficulty in analysing the randomness of such processes is the apparent tension between the notions of randomness and determinism: what type of randomness could exist in a deterministic process? Ergodic theory seems to offer a particularly promising theoretical tool for tackling this problem by positing a hierarchy, the so-called ‘ergodic hierarchy’ (EH), which is commonly assumed to provide a hierarchy of increasing degrees of randomness. However, that notion of randomness requires clarification. The mathematical definition of EH does not make explicit appeal to randomness; nor does the usual way of presenting EH involve a specification of the notion of randomness that is supposed to underlie the hierarchy. In this paper we argue that EH is best understood as a hierarchy of random behaviour if randomness is explicated in terms of unpredictability. We then show that, contrary to common wisdom, EH is useful in characterising the behaviour of Hamiltonian dynamical systems.     

重大件货装卸动态仿真系统中三维视景模型

重大件货具有尺度超长，重量超重且装运困难的特点，为了解这一难题，用ＶＣ＋和ＯＰＥＮＧＬ开发了重大件货动态仿真系统。详细介绍了系统中的三维视景显示模型，并在此基础上给出三维船体及其附属结构建模方法。     

海上安全中人为因素研究的几种方法

简叙引发海上交通安全事故的人为因素研究的几种方法，讨论了人为因素研究的各种方法在海上安全研究中的重要性及其适应范围，并通过具体实例对各种方法进行了分析和验证，可为相关部门提供船舶安全评估和检验的理论依据。     

Mathematics: Essential Tensions

The vivacity of mathematics results (partly) from the fact that mathematics is stretched between several poles, not being committed to any one. The paper presents the following polarities: realism - idealism, the finite - the infinite, the discrete - the continuous, the approximate - the exact, certitute - probability, simplicity - complexity, unity - multiplicity.