Global bifurcation structure of chaotic neural networks and its application to traveling salesman problems

This paper studies global bifurcation structure of the chaotic neural networks applied to solve the traveling salesman problem (TSP). The bifurcation analysis clarifies the dynamical basis of the chaotic neuro-dynamics which itinerates a variety of network states associated with possible solutions of TSP and efficiently ‘searches’ for the optimum or near-optimum solutions. By following the detailed merging process of chaotic attractors via crises, we find that the crisis-induced intermittent switches among the ruins of the previous localized chaotic attractors underly the ‘chaotic search’ for TSP solutions. On the basis of the present study, efficiency of the ‘chaotic search’ to optimization problems is discussed and a guideline is provided for tuning the bifurcation parameter value which gives rise to efficient ‘chaotic search’.     

心导纳微分环,肺导纳微分环最大向量正常值及其临床意义

本文报道３－５０岁２１４例心导纳微分环（ＣＡＤＬ）和肺导纳微分环（ＰＡＤＬ）最大向量振幅及方位正常值，结果随增龄变化振幅递减，方位递增，多数男＞女，部分组间有差异。４８例左向右分流先心病环体最大向量与肺动脉压之间呈平行关系，并探讨其临床意义。     

Remodeling Adult Nursing

This article describes a nursing education experience in which a critical thinking approach was planned and implemented. Background discussion on critical thinking concepts and related research provides a foundation for presentation of the Mackie teaching model. The model uses a community-based, family-centered scenario as the basis for developing problemfocused nursing intervention skills from a holistic viewpoint. Role expectations of students and faculty are outlined, and related implementation difficulties, together with their resolution strategies, are described. Evaluation methods and outcomes are reviewed in the conclusion.     

中国政治文明建设的价值选择

中国社会主义政治文明建设是既要置于人类政治文明的背景之中 ,又要具有中国特色。政治文明建设价值选择是对政治文明发展趋向的整体确认 ,必须从政治理念、政治制度、政治行为、政治关系层面来把握。人类政治文明同质价值选择主要体现在权力制约、人民主权、治理方式 ;中国政治文明特质价值即社会主义定向和中国国情 ,这种价值选择体现在制度形态、治理形态、文化形态之中。     

Automated lumen definition from 30 MHz intravascular ultrasound images

One prerequisite for standard clinical use of intravascular ultrasound imaging is rapid evaluation of the data. The main quantities to be extracted from the data are the size and the shape of the lumen. Until now, no accurate, robust and reproducible method to obtain the lumen boundaries from intravascular ultrasound images has been described. In this study, 21 different (semi-)automated binary-segmentation methods for determining the lumen are compared with manual segmentation to find an alternative for the laborious and subjective procedure of manual editing. After a preprocessing step in which the catheter area is filled with lumen-like grey values, all approaches consist of two steps: (i) smoothing the images with different filtering methods and (ii) extracting the lumen by an object definition method. The combination of different filtering methods and object definition methods results in a total of 21 methods and 80 experiments. The results are compared with a reference image, obtained from manual editing, by use of four different quality parameters—two based on squared distances and two based on Mahalanobis distances. The evaluation has been carried out on 15 images, of which seven are obtained before balloon dilation and eight after balloon dilation. While for the post-dilation images no definite conclusions can be drawn, an automated contour model applied to images smoothed with a large kernel appears to be a good alternative to manual contouring. For pre-dilation images a fully automated active contour model, initialized by thresholding, preceded by filtering with a small-scale median filter is the best alternative for manual delineation. The results of this method are even better than manual segmentation, i.e. they are consistently closer to the reference image than the average distance of all individual manual segmentations.     

健康成人135例心率变异性时域分析

目的：探讨国人心率变异时域分析各项指标的正常值。方法：应用清华－西安兰港监测系统对１３５例１８～７９岁健康成人连续２４ｈ动态心电图监测。结果：①心率变异性时域：ＳＤＮＮ、ＳＤＳＤ、ＳＤＡＮＮ、ＲＭＳＳＤ、ＰＮＮ５０分别为１２９．５２±２７．２５ｍｓ；２１．１８±８．２０ｍｓ；１１４．７８±２６．８４ｍｓ；３１．３６±１２．６７ｍｓ；８．５０ ± ７．８０ｍｓ，所测得正常值范围与国内外研究结果相似。②１８～３５岁组、３６～５９岁组，均与≥６０岁组有非常显著的差异（Ｐ＜０．０１，或Ｐ＜０．０５）。③各年龄组男女间ＳＤＮＮ、ＳＤＳＤ、ＰＮＮ５０无显著差异（Ｐ＞０．０５），但ＳＤＡＮＮ男性较女性大（Ｐ＜０．０５）；女性ＲＭＳＳＤ较男性大（Ｐ＜０．０５）。结论：ＳＤＮＮ＞１００ｍｓ；ＳＤＳＤ＞１２ｍｓ；ＳＤＡＮＮ＞８７ｍｓ；ＲＭＳＳＤ＞１８ｍｓ；ＰＮＮ５０＞０．７％可作为ＨＲＶ时域分析参考正常值。     

行列资料诊断试验预告值和准确度的一次性标化研究

本文建立了行列资料诊断试验预告值和准确度的一次性标化方法，省去了标化过程理论样本Ｎｔ的设定和求有关理论值的计算过程，导出行列资料中标准化Ⅰ级阳性预告值和标准化Ⅱ级阳性预告值、标准化Ⅰ级阴性预告值和标准化Ⅱ级阴性预告值、标准化可疑预告值和标准化准确度的一次性标化公式。分析了标化与非标化预告值的关系及转化规律。     

50岁以上正常人左室舒张期彩色多普勒血流频谱参数变化的研究

目的探讨５０岁以上正常人左室舒张期脉冲多普勒频谱的参数变化情况。方法选择一年半时间内受检的所有５０岁以上正常人４７５例，按每１０岁为一组分４组进行分析。受检者取左侧卧位，常规显示心尖四腔心切面，取样容积置于二尖瓣尖，使声束与二尖瓣血流方向夹角＜１５°，以连续三个心动周期的平均值分别测量Ｅ峰、Ａ峰、Ｅ／Ａ及Ｅ峰减速时间并统计。结果发现Ｅ峰高于正常值低限的例数、平均Ｅ峰血流速度以及Ｅ／Ａ均随着年龄的增加而下降，Ｅ峰减速时间则随着增龄而增加。结论左室舒张期血流频谱的所有参数与年龄有显著的相关性，明显随着增龄而变化，并且有其规律性。     

Numerical method for weights adjustment in minimax multi‐model LQ‐control

The minimax linear quadratic problem, where ‘max’ is taken over a finite set of indices (models) and ‘min’ is taken over the set of admissible controls, is considered. The solution is obtained by the robust optimal control application. The control turns out to be a linear combination of the controls optimal for each individual model. This paper develops a numerical method for the optimal weights adjustment. An example shows a quick convergence of the proposed procedure. Copyright © 2007 John Wiley & Sons, Ltd.     

Analysis of Intestinal Perfusion Data for Highly Permeable Drugs Using a Numerical Aqueous Resistance—Nonlinear Regression Method

Purpose. To develop, validate and apply a method for analyzing the intestinal perfusion data of highly permeable compounds using the Numerical Aqueous Resistance (NAR) theory and nonlinear regression (NAR-NLR) and to compare the results with the well-established Modified Boundary Layer (MBL) Analysis. Methods. The NAR-NLR method was validated and the results were compared to the MBL analysis results using previously reported cephradine jejunal perfusion data. Using the Single Pass Intestinal Perfusion (SPIP) method, the concentration dependence of intestinal permeability was investigated for formycin B, proline, and thymidine, three compounds reported to be absorbed by carrier-mediated transport processes. The MBL and NAR-NLR analyses were then applied to the three sets of SPIP data. Results. The results demonstrate that the intrinsic MBL transport parameters were highly variable and, in one case, the analyses failed to give a statistically significant Michaelis constant. The MBL mean dimensionless wall permeabilities (P*_w) were greater than the NAR-NLR P*_w and were also highly variable. In all cases, the NAR-NLR variability was significantly lower than the MBL variability. The extreme variability in the MBL-calculated P*_w is due to the sensitivity of P*_w when the fraction of unabsorbed drug (C_m/C_o) is low or, alternatively, when P*_w approached the aqueous permeability, P*_aq. Conclusions. The NAR-NLR method facilitates the analysis of intestinal perfusion data for highly permeable compounds such as those absorbed by carrier-mediated processes at concentrations below their K_m. The method also allows for the use of a wider range of flow conditions than the MBL analysis resulting in more reliable and less variable estimates of intestinal transport parameters as well as intestinal wall permeabilities.