Galaxies, human eyes, and artificial neural networks

The quantitative morphological classification of galaxies is important for understanding the origin of type frequency and correlations with environment. However, galaxy morphological classification is still mainly done visually by dedicated individuals, in the spirit of Hubble's original scheme and its modifications. The rapid increase in data on galaxy images at low and high redshift calls for a re-examination of the classification schemes and for automatic methods. Here are shown results from a systematic comparison of the dispersion among human experts classifying a uniformly selected sample of more than 800 digitized galaxy images. These galaxy images were then classified by six of the authors independently. The human classifications are compared with each other and with an automatic classification by an artificial neural network, which replicates the classification by a human expert to the same degree of agreement as that between two human experts.     

Chemical impurity produces extra compound eyes and heads in crickets

A chemical impurity isolated from commercially purchased acridine causes cricket embryos to develop extra compound eyes, branched antennae, extra antennae, and extra heads. Purified acridine does not produce similar duplications of cricket heads or head structures nor do the substituted acridines proflavine, acriflavine, or acridine orange. A dose-response relation exists such that the number and severity of abnormalities increase with increasing concentration of the teratogen.     

日本沼虾(Macrobrachium nipponense)孵化前后复眼发育的超微结构研究

利用电镜技术研究日本沼虾孵化前后复眼发育的超微结构,结果显示:(1)复眼内小眼折光系统包括角膜、角膜细胞及晶锥,晶锥周围有虹膜色素细胞分布。从产卵后第16 d到第Ⅰ期状幼体,小眼角膜厚度和晶锥直径逐渐增大,角膜细胞内细胞器数量逐渐增多;晶锥内电子致密颗粒区域由6块融合为4块,晶锥末端附近出现第8个小网膜细胞。(2)小眼感光系统由8个小网膜细胞组成,小网膜细胞伸出微绒毛组成“十足目型”感杆束,感杆束周围围绕一层较薄细胞质,胞质内外可见胞饮小泡及膜下储泡囊。随着胚胎发育,感杆束直径逐渐增大,小网膜细胞内线粒体、内质网等细胞器数量逐渐增多,并出现多囊体、板膜体、色素颗粒等结构。(3)胚胎发育过程中,小网膜细胞分化过程如下:产卵后第16 d,感杆束周围7个小网膜细胞间空隙较大,中间被第8个小网膜细胞4个分叶隔开,细胞内出现远端色素颗粒;第Ⅰ期状幼体,第8个小网膜细胞位置上升,其它7个小网膜细胞相互间排列紧密,细胞内出现大量近端色素颗粒。     

Spectral sensitivity of the compound eyes of Anomala corpulenta motschulsky(Coleoptera:Scarabaeoidea)

The scarab beetle, Anomala corpulenta Motschulsky(Coleoptera: Scarabaeoidea), is a widespread and destructive pest in China. Vision is one of the most important means of acquiring information about the external environment. In order to contribute to the understanding of the perception of visual stimuli in this species, the light sensitivity and spectral responses of the scarab beetle, A. corpulenta, were measured by using an electroretinogram(ERG) technique. In total, 14 monochromatic light intensities, between 340 and 605 nm, were applied to the compound eyes of A. corpulenta under varying levels of adaptation to dark and light conditions. The results showed that all light stimuli induced an ERG response, with varied amplitudes. The spectral sensitivity curve of dark-adapted eyes showed one major peak(~400 nm; near-ultraviolet), a secondary peak(from 498 to 562 nm; yellow-green) and the third peakat 460 nm. By contrast, in light-adapted eyes, only a near-UV peak was observed. From these results, we conclude that the compound eye of A. corpulenta is likely to have at least three spectral types of photoreceptor. Significance of differences were also recorded in the responses of male and female compound eyes, as well as diurnally and nocturnally. The amplitude of ERG in response to white-light stimuli varied with the light intensity: The stronger the luminance, the higher the ERG value. This suggests that the compound eye of A. corpulenta adapts quickly to changing light conditions, enabling A. corpulenta to maintain nocturnal activities.     

Spectral sensitivity of the compound eyes of Anomala corpulenta motschulsky (Coleoptera: Scarabaeoidea)

The scarab beetle, Anomala corpulenta Motschulsky (Coleoptera: Scarabaeoidea), is a widespread and destructive pest in China. Vision is one of the most important means of acquiring information about the external environment. In order to contribute to the understanding of the perception of visual stimuli in this species, the light sensitivity and spectral responses of the scarab beetle, A. corpulenta, were measured by using an electroretinogram (ERG) technique. In total, 14 monochromatic light intensities, between 340 and 605 nm, were applied to the compound eyes of A. corpulenta under varying levels of adaptation to dark and light conditions. The results showed that all light stimuli induced an ERG response, with varied amplitudes. The spectral sensitivity curve of dark-adapted eyes showed one major peak (~400 nm; near-ultraviolet), a secondary peak (from 498 to 562 nm; yellow-green) and the third peakat 460 nm. By contrast, in light-adapted eyes, only a near-UV peak was observed. From these results, we conclude that the compound eye of A. corpulenta is likely to have at least three spectral types of photoreceptor. Significance of differences were also recorded in the responses of male and female compound eyes, as well as diurnally and nocturnally. The amplitude of ERG in response to white-light stimuli varied with the light intensity: The stronger the luminance, the higher the ERG value. This suggests that the compound eye of A. corpulenta adapts quickly to changing light conditions, enabling A. corpulenta to maintain nocturnal activities.     

中药增效抗菌复方对人工诱发鸡大肠杆菌病的疗效试验

根据传统中兽医理论,中药增效抗菌复方由黄芩、秦皮、白头翁、苦参和甲氧苄啶按比例组成.采用人工诱发雏鸡大肠杆菌病的方法,以对分离株大肠杆菌较敏感的环丙沙星作为对照组,进行中药增效抗菌复方的预防和治疗试验,探索中药增效抗菌复方对鸡大肠杆菌病的防治效果.结果表明,预防用药组雏鸡的发病率和死亡率明显低于感染对照组,中、高剂量的...     

洋葱中的生物活性物质

洋葱为2a生或多年生植物,以肥大的肉质鳞茎为食用部分,营养极为丰富,含有较多的蛋白质、维生素,尤其是含有硫、磷、铁等多种矿物质,并且有特殊的辛辣味,合有挥发油、硫化物、类黄酮、甾体皂苷类和前列腺素类等化学成分,同时具有抗癌抑茵、降血糖、降血脂、抗血小板凝聚、抗氧化作用、预防心血管疾病和骨质疏松等功效。     

Biologically based computational models of high-level cognition

Computer models based on the detailed biology of the brain can help us understand the myriad complexities of human cognition and intelligence. Here, we review models of the higher level aspects of human intelligence, which depend critically on the prefrontal cortex and associated subcortical areas. The picture emerging from a convergence of detailed mechanistic models and more abstract functional models represents a synthesis between analog and digital forms of computation. Specifically, the need for robust active maintenance and rapid updating of information in the prefrontal cortex appears to be satisfied by bistable activation states and dynamic gating mechanisms. These mechanisms are fundamental to digital computers and may be critical for the distinctive aspects of human intelligence.     

华山松大小蠹成虫复眼的外部形态及显微结构

【目的】对华山松大小蠹雌雄成虫复眼的外部形态和内部结构进行研究,为进一步探索华山松大小蠹感光和光选择机制提供理论基础。【方法】应用扫描电镜与透射电镜对华山松大小蠹复眼的形态结构进行观察。【结果】华山松大小蠹复眼呈长椭圆形,位于头部两侧;眼表面光滑平坦,小眼间隙被覆有感觉毛。华山松大小蠹雌、雄成虫复眼的小眼组成数目分别为238~250和187~202;雌性小眼间隙着生有角膜乳突;复眼中心区域小眼呈正六边形,边缘区域的小眼为不规则的四边形或六边形。华山松大小蠹成虫复眼具有典型的无晶锥并列像眼。华山松大小蠹成虫复眼由1个角膜、1个晶锥体、2个初级色素细胞、8个小网膜细胞和其特化的视杆、若干个次级色素细胞和基膜构成。视杆属于半集中型视杆。【结论】华山松大小蠹雌雄成虫复眼具有相同的内部结构,但雌性成虫复眼分辨能力和可见距离稍优于雄性成虫。     

生物进化背景下人类的可持续发展

进化、适应和选择贯穿在任何一个物种的演化过程中,这是生物与环境相互联系、相互作用的结果,是大自然固有的运动规律在生物物种演化过程中的体现。只有准确地把握进化、适应和选择3者的内涵,以生物进化为主线,以人类可持续发展为中心,把人类对环境的主动适应和自然、社会对生物物种的方向性选择结合起来,从更深的层面上理解生物的进化和在生物进化背景下人类的可持续发展,才能在理论上和实践中坚持真正的达尔文主义和现代进化观及当代可持续发展观。     

Self-organization, embodiment, and biologically inspired robotics

Robotics researchers increasingly agree that ideas from biology and self-organization can strongly benefit the design of autonomous robots. Biological organisms have evolved to perform and survive in a world characterized by rapid changes, high uncertainty, indefinite richness, and limited availability of information. Industrial robots, in contrast, operate in highly controlled environments with no or very little uncertainty. Although many challenges remain, concepts from biologically inspired (bio-inspired) robotics will eventually enable researchers to engineer machines for the real world that possess at least some of the desirable properties of biological organisms, such as adaptivity, robustness, versatility, and agility.     

生物进化背景下人类的可持续发展(英文)

进化、适应和选择贯穿在任何一个物种的演化过程中,这是生物与环境相互联系、相互作用的结果,是大自然固有的运动规律在生物物种演化过程中的体现。只有准确地把握进化、适应和选择三者的内涵,以生物进化为主线,以人类可持续发展为中心,把人类对环境的主动适应和自然、社会对生物物种的方向性选择结合起来,从更深的层面上理解生物的进化和在生物进化背景下人类的可持续发展,才能在理论上和实践中坚持真正的达尔文主义和现代进化观及当代可持续发展观。     

Stimuli-responsive polymer nanocomposites inspired by the sea cucumber dermis

Sea cucumbers, like other echinoderms, have the ability to rapidly and reversibly alter the stiffness of their inner dermis. It has been proposed that the modulus of this tissue is controlled by regulating the interactions among collagen fibrils, which reinforce a low-modulus matrix. We report on a family of polymer nanocomposites, which mimic this architecture and display similar chemoresponsive mechanic adaptability. Materials based on a rubbery host polymer and rigid cellulose nanofibers exhibit a reversible reduction by a factor of 40 of the tensile modulus, for example, from 800 to 20 megapascals (MPa), upon exposure to a chemical regulator that mediates nanofiber interactions. Using a host polymer with a thermal transition in the regime of interest, we demonstrated even larger modulus changes (4200 to 1.6 MPa) upon exposure to emulated physiological conditions.