Prolonged poststrike elevation in tongue-flicking rate with rapid onset in gila monster,Heloderma suspectum: Relation to diet and foraging and implications for evolution of chemosensory searching

Experimental tests showed that poststrike elevation in tongue-flicking rate (PETF) and strike-induced chemosensory searching (SICS) in the gila monster last longer than reported for any other lizard. Based on analysis of numbers of tongue-flicks emitted in 5-min intervals, significant PETF was detected in all intervals up to and including minutes 41–45. Using 10-min intervals, PETF lasted though minutes 46–55. Two of eight individuals continued tongue-flicking throughout the 60 min after biting prey, whereas all individuals ceased tongue-flicking in a control condition after minute 35. The apparent presence of PETF lasting at least an hour in some individuals suggests that there may be important individual differences in duration of PETF. PETF and/or SICS are present in all families of autarchoglossan lizards studied except Cordylidae, the only family lacking linguallly mediated prey chemical discrimination. However, its duration is known to be greater than 2-min only in Helodermatidae and Varanidae, the living representatives of Varanoidea. That prolonged PETF and SICS are typical of snakes provides another character supporting a possible a varanoid ancestry for Serpentes. Analysis of 1-min intervals showed that PETF occurred in the first minute. A review of the literature suggests that a pause in tongue-flicking and delay of searching movements are absent in lizards and the few nonvenomous colubrid snakes tested. The delayed onset of SICS may be a specific adaptation of some viperid snakes to allow potentially dangerous prey to be rendered harmless by venom following voluntary release after envenomation and preceding further physical contact with the prey.     

Human eye sclera detection and tracking using a modified time-adaptive self-organizing map

This paper investigates the use of time-adaptive self-organizing map (TASOM)-based active contour models (ACMs) for detecting the boundaries of the human eye sclera and tracking its movements in a sequence of images. The task begins with extracting the head boundary based on a skin-color model. Then the eye strip is located with an acceptable accuracy using a morphological method. Eye features such as the iris center or eye corners are detected through the iris edge information. TASOM-based ACM is used to extract the inner boundary of the eye. Finally, by tracking the changes in the neighborhood characteristics of the eye-boundary estimating neurons, the eyes are tracked effectively. The original TASOM algorithm is found to have some weaknesses in this application. These include formation of undesired twists in the neuron chain and holes in the boundary, lengthy chain of neurons, and low speed of the algorithm. These weaknesses are overcome by introducing a new method for finding the winning neuron, a new definition for unused neurons, and a new method of feature selection and application to the network. Experimental results show a very good performance for the proposed method in general and a better performance than that of the gradient vector field (GVF) snake-based method.     

基于预处理的Ballon模型及在眼疲劳检测中的应用

获取眼睛轮廓和眼球轮廓对进一步研究人眼疲劳状态具有重要意义.提出基于预处理的Ballon模型对含有双眼的局部人脸图片进行人眼和眼球检测的方法.用微分算法抽取边缘、标识出物体、使用几何特性识别人艰区域,自动获取主动轮廓所需要的眼睛初始轮廓;使用提出的基于预处理的Ballon模型收敛人眼;结合数学形态等方法收敛到眼球.实验结果表明,该方法具有效果好、鲁棒性好、受光线影响弱等优点.     

Engineering of protein epitopes: a single deletion in a snake toxin generates full binding capacity to a previously unrecognized antibody

Structural features associated with the ability of a monoclonalantibody (mAb) to discriminate between protein variants areidentified and engineered. The variants are the curaremimetictoxin from Naja nigricollis and erabutoxin a or b from Laticaudasemifasciata which differ from each other by 16 substitutionsand one insertion. The neutralizing mAb M1 recognizes with highaffinity a topographical epitope on the surface of toxin , butfails to recognize the erabutoxins although they possess mostof the residues forming the presumed epitope. Examinations ofthe toxin and erabutoxin 3-D structures and molecular dynamicssimulations reveal several differences between the variants.In particular, the region involving the ß-turn 17–24is organized differently. Analysis of the differences foundin this region suggests that the insertion (or deletion) atposition 18 of the variant amino add sequences is particularlyimportant in determining the differential cross-reactivity.To test this proposal, residue 18 was deleted in one erabutoxinusing sitedirected mutagenesis, and the biological propertiesof the resulting mutant were examined. We found that full antigenicitywas restored in the previously unrecognized variant. The implicationsof this finding are discussed.     

基于极坐标中蛇模型的类圆目标轮廓提取技术研究

提出了转化到极坐标中的蛇模型.通过把蛇模型转化到极坐标中,使轮廓的候选点得以更有序的排列.由于采用了动态规划法并在整个能量空间中搜索能量泛函的极值,算法对能量泛函的局部极值有较强的鲁棒性.所提出的模型不需要确定初始轮廓,可以用非迭代方法直接求解.与传统的动态规划法和贪婪算法进行了比较实验.结果表明,所提出的算法对极坐标中极点的位置不是很敏感.     

基于Snake模型的虹膜定位算法

虹膜识别被认为是目前最准确可靠的生物特征识别方法．快速、准确地定位虹膜是虹膜识别系统的关键．提出一种基于Snake模型的虹膜定位算法：采用Canny检测算子定位虹膜内边缘，运用Snake模型锁定虹膜外边缘．实验表明，该方法速度快、精度高，并且具备良好的鲁棒性．     

Snake Mating Systems, Behavior, and Evolution: The Revisionary Implications of Recent Findings.

Sexual selection and mating systems profoundly influence the behavior and psychology of animals. Using their own studies of green anacondas (Eunectes murinus) and reviewing other recent studies, the authors conclude that incomplete data derived from a few well-studied snake species have led to general acceptance of polygyny as the dominant mating system in snakes. New data on behavior, paternity, and life history in a diverse taxonomic array of snakes support the view that polyandry is not only common in snakes but may have been the ancestral mating system. This interpretation helps to explain many seemingly paradoxical behavioral differences between lizards and snakes, such as the lack of territorial systems in most snakes and their frequent female-biased sexual size dimorphism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modular Reconfigurable Robots in Space Applications

Robots used for tasks in space have strict requirements. Modular reconfigurable robots have a variety of attributes that are well suited to these conditions, including: serving as many different tools at once (saving weight), packing into compressed forms (saving space) and having high levels of redundancy (increasing robustness). In addition, self-reconfigurable systems can self-repair and adapt to changing or unanticipated conditions. This paper will describe such a self-reconfigurable modular robot: PolyBot. PolyBot has significant potential in the space manipulation and surface mobility class of applications for space.     

蛇形机器人侧向运动的研究

本文提出了一种新型蛇形机器人机构，建立了其空间运动学模型，实现了蛇形 机器人的两种侧向运动：侧向蜿蜒运动和侧向滚动，前者通过调节两个异相波的频率比，实 现了任意方向的侧向运动．后者通过控制运动波的幅值变化，实现了各种形式的纯侧向移动 ，当幅值足够大时，这种侧向滚动可以跨越障碍．     

基于恒定曲率变化的主动轮廓模型

随着主动轮廓模型（又称snake模型）被广泛应用于无人参与的自动化任务,人们对模型的鲁棒性和自适应能力提出了更高的要求.而传统内部力模型的收缩效应,过平滑作用,及缩放可变性,导致了内部力模型的参数调整困难,很难由程序自动进行调整.据此,提出了基于恒定曲率变化的内部力模型.该模型不仅具有缩放不变性,而且在保证轮廓光滑连续的同时,未引入其他的副作用（如收缩,过平滑等）,提高了模型参数的鲁棒性.实验结果表明,该模型精确提取目标轮廓的能力得到增强,能够成功提取存在高曲率位置的凹陷轮廓,而且内部力大小衰减迅速,对轮廓点的增删不敏感,保证了模型快速稳定地收敛到期望轮廓.