Whole-body amino acid pattern of F-4 human growth hormone gene-transgenic red common carp (Cyprinus carpio) fed diets with different protein levels

F-4 generation of human growth hormone (hGH) gene-transgenic red common carp, and the non-transgenic controls were fed for 8 weeks on purified diets with 20%, 30% or 40% protein. Analysis of whole-body amino acids showed that the proportions of lysine, leucine, phenylalanine, valine and alanine, as percentages of body protein, increased significantly, while those of arginine, glutamic acid and tyrosine decreased, with increases in dietary protein level in at least one strain of fish. Proportions of the other amino acids were unaffected by the diets. The proportions of lysine and arginine were significantly higher, while those of leucine and alanine were lower in the transgenics than in the controls in at least one diet group. Proportions of the other amino acids were unaffected by strain. The results suggest that the whole-body amino acid profile of transgenic carp, when expressed as proportions of body protein, was in general, similar to that of the non-transgenic controls. (C) 2000 Elsevier Science B.V. All rights reserved.

基于栅格邻域可视性相关的最优路径问题的研究

基于可视性的最优路径分析是地形可视性分析中的一项基本功能，属于空间决策支持的范畴，在理论研究和实际应用两方面都具有重要的意义。在传统基于可视性的最优路径分析中，影响通行能力的可视性代价信息为相互独立的0维数值。然而，用0维无关的代价来表示三维地形上点的可视性信息是不全面的，有必要采用一维或更高维的代价表达方式。本文用二维视域来描述三维可视性信息，考虑到邻近点的二维视域相互重叠造成的可视性相关性对最优路径搜索的影响，提出基于栅格邻域可视性相关的最优路径问题。本文对该问题的分类和求解进行了详细的分析和讨论。 本文的创新性工作如下： (1) 改进了传统基于可视性的最优路径搜索问题。对于存在的“真实性”不足之处，考虑地形特征如土地覆盖或土地利用，障碍物及坡度等对通行能力的影响，并将这些影响和可视性信息一起添加到传统的基于可视性的最优路径搜索过程中，所得结果更加符合实际情况。 (2) 提出并求解了一类基于栅格邻域可视性相关的最优路径问题：基于平均视距最小/最大的可视覆盖路径问题。在可视覆盖最优和路径长度最优两个约束条件下，用代表路径平均视野的开阔程度的平均视距来衡量最优可视覆盖路径问题的最优性。通过对平均视距及该类问题目标函数进行建模分析以及预先计算并存储整个地形上的视域信息，用基于视域融合操作的模拟退火算法实现了该类问题的求解。 (3) 提出并求解了一类基于栅格邻域可视性相关的最优路径问题：最小可视覆盖路径问题。在只考虑可视覆盖最优的约束条件下，用代表路径视野开阔程度即“可视覆盖面积”来衡量最优可视覆盖路径问题的最优性。通过对问题目标函数建模及求解方法的比较分析，用Dijkstra算法实现了该类问题的求解。 最后，本文比较了基于栅格邻域可视性相关的和传统基于可视性无关的最不可视路径问题得到的结果。通过对新方法和传统方法应用于求解走私路径所得结果的定量和定性的分析与对比，得出新方法比传统方法准确的结论。

Diet and feeding behavior of Rhinopithecus bieti at Xiaochangdu, Tibet: Adaptations to a marginal environment

The diet and feeding ecology of a wild subpopulation of black-and-white snub-nosed monkeys (Rhinopithecus bieti) were studied at Xiaochangdu in Honglaxueshan Nature Reserve, Tibet. This region is climatologically harsher than any other inhabited by non-human primates. Black-and-white snub-nosed monkeys fed on 48 parts of 25 plant species, at least three species of lichens and seven species of invertebrates. The number of food items exploited varied markedly among seasons, with dietary diversity being greatest in spring and summer. In winter, black-and-white snub-nosed monkeys had to subsist on fallback foods such as dried grass and bark. Ubiquitous lichens formed a major dietary constituent throughout the year, contributing about 75% of feeding records. Even though lichens act as a staple, our findings signify that the monkeys at Xiaochangdu prefer feeding on foliage, which is higher in protein content than the former. We provide evidence that black-and-white snub-nosed monkeys are able to cope with an array of food items other than lichens and hence can be regarded as feeding generalists. We discuss the results with reference to previous studies on other subpopulations living in habitats that are floristically more diverse and offer more plant food items than the marginal habitat at Xiaochangdu.

Quantifying robustness and dissipation cost of yeast cell cycle network: The funneled energy landscape perspectives

We study the origin of robustness of yeast cell cycle cellular network through uncovering its underlying energy landscape. This is realized from the information of the steady-state probabilities by solving a discrete set of kinetic master equations for the network. We discovered that the potential landscape of yeast cell cycle network is funneled toward the global minimum, G1 state. The ratio of the energy gap between G1 and average versus roughness of the landscape termed as robustness ratio ( RR) becomes a quantitative measure of the robustness and stability for the network. The funneled landscape is quite robust against random perturbations from the inherent wiring or connections of the network. There exists a global phase transition between the more sensitive response or less self-degradation phase leading to underlying funneled global landscape with large RR, and insensitive response or more self-degradation phase leading to shallower underlying landscape of the network with small RR. Furthermore, we show that the more robust landscape also leads to less dissipation cost of the network. Least dissipation and robust landscape might be a realization of Darwinian principle of natural selection at cellular network level. It may provide an optimal criterion for network wiring connections and design.

Carbon transition efficiency and process cost in high-rate, large-area deposition of diamond films by DC arc plasma jet

A new DC plasma torch in which are jet states and deposition parameters can be regulated over a wide range has been built. It showed advantages in producing stable plasma conditions at a small gas flow rate. Plasma jets with and without magnetically rotated arcs could be generated. With straight are jet deposition, diamond films could be formed at a rate of 39 mu m/h on Mo substrates of Phi 25 mm, and the conversion rate of carbon in CH4 to diamond was less than 3%. Under magnetically rotated conditions, diamond films could be deposited uniformly in a range of Phi 40 mm at 30 mu m/h, with a quite low total gas flow rate and high carbon conversion rate of over 11%. Mechanisms of rapid and uniform deposition of diamond films with low gas consumption and high carbon transition efficiency are discussed.

Weighted least-squares phase unwrapping algorithm based on derivative variance correlation map

Among different phase unwrapping approaches, the weighted least-squares minimization methods are gaining attention. In these algorithms, weighting coefficient is generated from a quality map. The intrinsic drawbacks of existing quality maps constrain the application of these algorithms. They often fail to handle wrapped phase data contains error sources, such as phase discontinuities, noise and undersampling. In order to deal with those intractable wrapped phase data, a new weighted least-squares phase unwrapping algorithm based on derivative variance correlation map is proposed. In the algorithm, derivative variance correlation map, a novel quality map, can truly reflect wrapped phase quality, ensuring a more reliable unwrapped result. The definition of the derivative variance correlation map and the principle of the proposed algorithm are present in detail. The performance of the new algorithm has been tested by use of a simulated spherical surface wrapped data and an experimental interferometric synthetic aperture radar (IFSAR) wrapped data. Computer simulation and experimental results have verified that the proposed algorithm can work effectively even when a wrapped phase map contains intractable error sources. (c) 2006 Elsevier GmbH. All rights reserved.