大口鲶池塘养殖试验初报

利用当年繁殖的大规格鱼种,以不同规格及密度进行大口鲶池塘单养试验,并对饲料配制及投饲方面作了新的探索。经过3个月的饲养,平均体重分别达到443、670.7、211.6g/尾,成活率分别为99.1、99.0、98.6％,平均饲料系数分别为3.2、2.9、3.6:1,日总平均增重分别为3.8、5.1、1.8g/尾·天。     

NONLINEAR RESPONSE STUDIES OF TALL STEEL FRAMES

Considerable eftects of geometric nonlinearity upon tallsteel frames and flexibly jointed steel frames are recognized.Systematicanalysis philosophy of geometric nonlinearity under various coordinatesystems and its corresponding explicit expression of tangent stiffness matrices are comprehensively embodied.The entries in tangent stiffnessmatrices with its nonlinear behavior and its abstrusely implied physicmeanings are expounded and a straight forward derivation technique ofnonlinear matrices is given.A computer algorithm which can performwhole range studies of steel frames by considering geometric and materialnonlinearities up to the ultimate load carrying capacity is implemented.     

鲶鱼体表黏液特性的初步研究

对鲶鱼体表黏液活性成分、抑菌特性进行研究,并对蛋白类物质和多糖类物质含量进行测定,结果表明:(1)使用G-200葡聚糖凝胶层析法对鲶鱼体表黏液活性成分进行分离,无法得到纯化的单一物质,在以后的试验中需要寻找新的分离纯化方法。(2)鲶鱼体表黏液对藤黄色葡萄球菌、大肠杆菌、枯草杆菌抑菌效果不明显。(3)鲶鱼体表黏液中含有的蛋白类物质含量占黏液干重的40%左右,多糖类物质约占黏液干重的4.2%。     

A novel keyframe extraction method based ondynamic time-domain detection windows

Real-time keyframe extraction is significant for the on-line video retrieval and recognition system. It will lead to low speed for keyframe extraction by analyzing the frames one by one on the basis of shots detection. A novel keyframes extraction method based on dynamic time-domain detection windows is presented. The video frame-sequence is divided into video units with different lengths. The frames at the edges of the window and the sampled frames inside the window are analyzed to judge the changes of the unit content. Meanwhile, a hybrid growth mode of windows and slow detection mechanism are proposed to ensure the quality and speed of the keyframe extraction. The extracted keyframes are clustered to obtain the best keyframe. The experiments show that the proposed method has a good comprehensive performance for different kinds of videos.     

Risk frames on shark diving websites: implications for global shark conservation

• 1. Decision‐makers can leverage understanding about the human dimensions (HD) of shark conservation to inform more effective conservation action. Characterizing risk frames on shark diving websites can provide insight about the HD of shark conservation and deepen understanding of the role of risk in influencing human relationships with wildlife.
• 2. The objectives of the current study were to: (1) describe risk frames (e.g. victim, perpetrator) found on shark diving websites; (2) explore themes among and between risk frames; and (3) synthesize implications for conservation.
• 3. Content among 53 websites was analysed in December 2008; 15% used only a perpetrator frame, 21% used only a victim frame, 36% used both frames and 28% used neither frame.
• 4. Websites with a conservation link were more likely to use a victim frame (T = 0.283, P<0.05). The occurrence of both frames on study websites speaks to the relevancy of applying risk‐related thinking to shark conservation.
• 5. This research highlights how risk frames are contextualized on selected shark diving websites. Integrated with understanding of the ecological processes surrounding sharks and their conservation, HD information such as that presented here can contribute to more effective shark conservation. Copyright © 2011 John Wiley & Sons, Ltd.

     

Seasonal dynamics in gonadotropin secretion and E2-binding in the catfish Heteropneustes fossilis

In the present investigation, significant annual/seasonal variations were noticed in plasma and pituitary gonadotropin (GTH) which were correlated with gonado-somatic index, plasma estradiol-17β, and nuclear E₂ receptor (NE₂R) in the pituitary, hypothalamus and telencephalon. The NE₂R concentrations and dissociation constant (k _d) values showed significant seasonal variations with high values in the late preparatory phase and low values in the postspawning phase. The NE₂R levels were the highest in the pituitary, followed by the hypothalamus and telencephalon in all the seasons. In the prespawning phase, ovariectomy (OVX) elicited a strong negative feedback on GTH secretion with a bimodal pattern of release and elevated the NE₂R levels and k _d values, without producing any significant change in the resting phase suggesting that E₂ appears to exert differential feedbacks on GTH secretion.     

Analysis on the effect of substation structure on grounding grid corrosion diagnosis

The measured data of grounding grid corrosion diagnosis are often influenced by steel structural frames, and thus the diagnosis is inaccurate. Based on grounding grid corrosion diagnosis theory, the characteristics of structure frames number, length, layout location and resistance of the influence on the diagnosis result are analyzed by establishing the simulation model. The results show that regardless of the structural frames’ number, layout location and span length, the existence of structural frames reduces the diagnosis sensitivity of fault branch which is near structural frames, making the extent of diagnosed branch corrosion is lower than that without framing. However, the diagnosed corrosion of the branch which is away from the structural frames won’t be influenced. The bigger the resistance of the structural frames connected to grounding grid, the smaller the diagnosis result of interference. Choose the grounding grid branch which has no obvious increase multiples near structural frames as excavation object can improve the diagnostic accuracy.     

TaULP5 contributes to the compatible interaction of adult plant resistance wheat seedlings-stripe rust pathogen

Adult plant resistance indicates that plant is susceptible to pathogen at seedling stage, but resistant at adult stage. Understanding the mechanism of the interactions between APR wheat plants and Puccinia striiformis f. sp. tritici (Pst) is important for the creation of strategies to improve cultivar disease resistance. In this study, a full-length cDNA was isolated from APR wheat cultivar Xingzi 9104 (XZ), and was designated as ubiquitin-like protein 5 (TaULP5). TaULP5 was likely to be located in the cytoplasm, with a percentage of 75.9% Arabidopsis protoplasts number. The expression of TaULP5 was largely induced in the compatible interaction of wheat seedlings to Pst, while no obvious change was found in the incompatible interaction of wheat adult plants to Pst. Moreover, when TaULP5 was knocked down, the wheat resistance at seedling stage to Pst was improved. In addition, knockdown of TaULP5 increased the expression levels of some biotic stress-related genes, such as PR1 and PR2. It is the first time to confirm that ubiquitin-like protein could contribute to the compatible interaction of XZ to Pst, and the results will lay a foundation for understanding the mechanisms of different interactions between APR wheat plants and Pst at post-translational level.