二阶系统变结构控制u选取策略的研究

针对二阶系统提出了一种较简单的控制ｕ的选取策略，从理论上证明了这种选取策略的稳定性，并以８０３１单片机实现变结构控制算法，通过实际的超声测距系统的仿真和实验证明了这种控制ｕ的选取策略是正确的。     

利用伪随机序列相关辨识检测视觉诱发电位

诱发电位在临床诊断及中枢神经系统的研究中有重要意义。目前的诱发电位检测方法是平均法，由平均法获得的诱发电位远不能满足许多实际应用的需要。本文利用伪随机序列相关辨识技术，实现了快速检测视觉诱发电位。文中对这项技术的原理作了详细的描述，给出了检测算法，并分析了检测信噪比相对平均法的改善情况。实验结果显示，这项技术能大大缩短检测时间，对克服时变因素的影响，减少病人的痛苦，以及对诱发电位在神经外科手术中的应用都有深远意义。     

Optimization of Time-Varying Parking Charges and Parking Supply in Networks with Multiple User Classes and Multiple Parking Facilities

The optimization of parking charges and parking supply over the time of a day is an important problem in the design of transportation networks. This paper presents a bilevel model to determine the opti-mal time-varying parking charges and parking supply in road networks with multiple user classes and different types of parking facilities. The upper level of the model aims to maximize the network net benefit in response to the parking charges and parking supply, whereas the lower level is a time-dependent network equilibrium problem with elastic demand. A descent-gradient-based solution algorithm is adapted to solve the model. The numerical results show that the implementation of time-varying parking charges and parking supply is useful to effectively cater to the time-varying demand with different parking needs. The model provides a powerful tool for strategically designing parking locations and evaluating various parking policies.     

Programmed cell death, mitochondria and the plant hypersensitive response.

The plant response to attempted infection by microbial pathogens is often accompanied by rapid cell death in and around the initial infection site, a reaction known as the hypersensitive response. This response is associated with restricted pathogen growth and represents a form of programmed cell death (PCD). Recent pharmacological and molecular studies have provided functional evidence for the conservation of some of the basic regulatory mechanisms underlying the response to pathogens and the activation of PCD in animal and plant systems. In animals, the mitochondrion integrates diverse cellular stress signals and initiates the death execution pathway, and studies indicate a similar involvement for mitochondria in regulating PCD in plants. But many of the cell-death regulators that have been characterized in humans, worms and flies are absent from the Arabidopsis genome, indicating that plants probably use other regulators to control this process.     

改进PF算法对红外图像中瞳孔的跟踪

提出一种基于粒子滤波的红外目标跟踪的新算法. 用该算法对采样粒子进行优化,改进了重采样环节,在不影响跟踪准确率的条件下,提高了算法的速度. 实验结果表明,将此算法运用到瞳孔跟踪中,跟踪比较准确有效. 同时,将Hough变换应用到了瞳孔边缘的定位领域中,此算法有效改进了红外图像中眼睛瞳孔的跟踪效果.     

CLOTHING COLOUR PREFERENCES IN A HOSPITAL ENVIRONMENT IN HONG KONG: PART I - CHILD PATIENT''''S PREFERENCES OF COLOUR ON NURSE UNIFORM

The aim of this study explored the importance of colour application on clothing and investigated whether there is a preference of colour on clothing among children under hospital environment. A modified colour associated test based on the Luster Color Test was used to carry out the survey. Fifty child patients aged four to sixteen were asked to look at two specially designed colour cards and to name their preferences and associations on each of the colour.     

Postnatal isl1+ cardioblasts enter fully differentiated cardiomyocyte lineages

The purification, renewal and differentiation of native cardiac progenitors would form a mechanistic underpinning for unravelling steps for cardiac cell lineage formation, and their links to forms of congenital and adult cardiac diseases. Until now there has been little evidence for native cardiac precursor cells in the postnatal heart. Herein, we report the identification of isl1+ cardiac progenitors in postnatal rat, mouse and human myocardium. A cardiac mesenchymal feeder layer allows renewal of the isolated progenitor cells with maintenance of their capability to adopt a fully differentiated cardiomyocyte phenotype. Tamoxifen-inducible Cre/lox technology enables selective marking of this progenitor cell population including its progeny, at a defined time, and purification to relative homogeneity. Co-culture studies with neonatal myocytes indicate that isl1+ cells represent authentic, endogenous cardiac progenitors (cardioblasts) that display highly efficient conversion to a mature cardiac phenotype with stable expression of myocytic markers (25%) in the absence of cell fusion, intact Ca2+-cycling, and the generation of action potentials. The discovery of native cardioblasts represents a genetically based system to identify steps in cardiac cell lineage formation and maturation in development and disease.     

Association of the T-cell regulatory gene CTLA4 with susceptibility to autoimmune disease

Genes and mechanisms involved in common complex diseases, such as the autoimmune disorders that affect approximately 5% of the population, remain obscure. Here we identify polymorphisms of the cytotoxic T lymphocyte antigen 4 gene (CTLA4)--which encodes a vital negative regulatory molecule of the immune system--as candidates for primary determinants of risk of the common autoimmune disorders Graves' disease, autoimmune hypothyroidism and type 1 diabetes. In humans, disease susceptibility was mapped to a non-coding 6.1 kb 3' region of CTLA4, the common allelic variation of which was correlated with lower messenger RNA levels of the soluble alternative splice form of CTLA4. In the mouse model of type 1 diabetes, susceptibility was also associated with variation in CTLA-4 gene splicing with reduced production of a splice form encoding a molecule lacking the CD80/CD86 ligand-binding domain. Genetic mapping of variants conferring a small disease risk can identify pathways in complex disorders, as exemplified by our discovery of inherited, quantitative alterations of CTLA4 contributing to autoimmune tissue destruction.