Rhythmic Movement of a Pair of One-Link Arms: Coordination by Intermittent Control

This paper considers the coordination and control of periodic movements of a pair of one-link arms. The system consists of two one-link arms each controlled by two muscle-like actuators. The muscle-like actuators are activated by simulated neural inputs. The model is simple enough to analyze, yet it embodies many aspects of human arms. Three attributes of the rhythmic coordinated movement of two arms, namely frequency, magnitude, and relative phase, are the only inputs to the controller. The controller uses mild co-activation and primarily activates the agonist. The effects of transmission delays, present in the reflex loop of physiological systems, also are modeled. The results of this research indicate the feasibility of controlling oscillatory body movements with short periods of activation. The result of many simulations, by varying the frequency or amplitude of the movement, indicate that the apparent lack of a simple relationship between neural control and desired behavior of the system should not be mistaken as evidence for the absence of a causal relationship between the activation patterns of the muscles and the desired behavior. Simulations of this system show stable oscillations at different frequencies and magnitudes even with additive noise and changes in the system mass.     

双向电泳-质谱技术筛选肝癌血清标记物

采用双向电泳 - 质谱技术筛选肝癌特异的血清蛋白标记物,以利于肝癌的早期诊断和治疗 . 肝癌、肝炎和正常三组各 20 例血清先采用超声、高丰度蛋白去除、脱盐预处理以优化双向电泳,图像分析三组血清图谱寻找差异点,基质辅助激光解吸飞行时间质谱对差异点进行鉴定 . 结果显示,通过样品预处理,血清上样体积平均增加 3 ～ 4 倍,参考胶点数由 218 个增至 332 个,白蛋白和免疫球蛋白明显减弱,水平条带明显减少 . 图谱比较所得 37 个差异点,经鉴定为 7 种蛋白 . 与正常组比较,转铁蛋白、甲状腺素运载蛋白在肝炎和肝癌组低表达,α-1 抗胰蛋白酶、凝聚素、铜蓝蛋白、触珠蛋白在肝炎和肝癌组均高表达 . α-1 抗胰蛋白酶在肝癌组较肝炎组高表达,而热休克蛋白 27 只在肝癌组表达 . 上述结果提示,双向电泳-质谱技术可发现肝癌发生发展过程中血清蛋白表达谱质或量的变化,从而为肝癌的早期诊断及治疗奠定基础 .     

Two synonymy cases within the genus Neoseiulella (Acari: Phytoseiidae): is the molecular evidence so evident?

Synonymy is considered as a great problem for diversity characterization and further applications, especially for biological control success with regard to the accurate identification of natural enemies. The present study focuses on two synonymy cases of natural enemies, belonging to the family Phytoseiidae, the genus Neoseiulella, specifically five species of this genus: Neoseiulella tiliarum, Neoseiulella formosa, Neoseiulella aceri, Neoseiulella squamiger, and Neoseiulella aceris. Morphological and molecular analyses [12S rRNA, cytochrome b (Cytb) mitochondrial (mt)DNA, internal transcribed spacer DNA] were applied. First, the results obtained support the synonymy of N. tiliarum and N. formosa. Second, because morphological differences (solenostomes occurrence) were observed for the first time between the type material of N. aceris and N. squamiger, the present study does not provide sufficient evidence to synomymize these two species and further analyses are required. Lastly, we assume that N. squamiger and N. aceri are synonyms. However, three groups of specimens, including N. aceri and N. squamiger, were identified by two mitochondrial DNA genes (12S rRNA and Cytb mtDNA). Therefore, the present study highlights the problems encountered when using only mitochondrial genes to diagnose species. The great mtDNA variations observed appear to reflect population differentiation (linked to plant support). This is the first time that such high intraspecific differentiation is be observed within the family Phytoseiidae. Further experiments, such as cross‐breeding and microsatellite DNA marker analyses, are planned to characterize gene flow and reproductive isolation levels within this species. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 323–344.     

Rhythmic Movement of a Pair of One-Link Arms: Coordination by Intermittent Control

This paper considers the coordination and control of periodic movements of a pair of one-link arms. The system consists of two one-link arms each controlled by two muscle-like actuators. The muscle-like actuators are activated by simulated neural inputs. The model is simple enough to analyze, yet it embodies many aspects of human arms. Three attributes of the rhythmic coordinated movement of two arms, namely frequency, magnitude, and relative phase, are the only inputs to the controller. The controller uses mild co-activation and primarily activates the agonist. The effects of transmission delays, present in the reflex loop of physiological systems, also are modeled. The results of this research indicate the feasibility of controlling oscillatory body movements with short periods of activation. The result of many simulations, by varying the frequency or amplitude of the movement, indicate that the apparent lack of a simple relationship between neural control and desired behavior of the system should not be mistaken as evidence for the absence of a causal relationship between the activation patterns of the muscles and the desired behavior. Simulations of this system show stable oscillations at different frequencies and magnitudes even with additive noise and changes in the system mass.     

Estimation of the Outcrossing Rate on Dryobalanops aromatica Gaertn. f. in Primary and Secondary Forests in Brunei, Borneo, Southeast Asia

Abstract Dryobalanops aromatica is an emergent canopy tree species with hermaphroditic bee-pollinated flowers. This species is distributed in the lowland dipterocarp forests of Malaya, Sumatra, Rhio Archipelago and Borneo. The flowering of many different dipterocarp species was observed in some parts of Brunei in 1991, and all over Brunei in 1992. The outcrossing rates of D, aromatica were estimated in 1991 and 1992 in the secondary forest, and in 1992 in the primary forest. Selective harvesting of D. aromatica has occurred in the secondary forest about 20 years ago. Four enzyme systems with a total of six isozyme loci were used to estimate the single locus and the multilocus outcrossing rates. The multilocus outcrossing estimates ranged from 0.794 to 0.856, with a mean of 0.816. These estimates are similar to those for other tropical tree species. Although the flowering density of D. aromatica in the secondary forest was lower than in the primary forest, the multilocus outcrossing estimates were not significantly different. The variation between years in the secondary forest was also not significant. These findings may be largely the result of the high flowering tree density of this species, even in the secondary forest. In this study, the outcrossing rates of D. aromatica were maintained by high flowering density regardless of the size structure or the topography of the habitat.