Amplification due to spatial clustering in an individual-based model of mosquito-avian arbovirus transmission

Theory and observations indicate that spatial clustering of birds and mosquitoes may be necessary for epizootic amplification of arboviruses with avian zoonoses. In this paper, I present an individual-based model of zoonotic arbovirus transmission among birds and mosquitoes. The results of initial ensemble model simulations indicate that the co-location of a vector mosquito oviposition site with an infected bird roost increases the local vector-to-host density and increases the likelihood of arbovirus amplification within the infected roost. Such amplification also increases the likelihood of secondary amplification at other roost sites, produces higher vector and host infection rates, increases the time to virus extinction within the model population, and increases the total number of birds infected. Additional oviposition locations within the model domain also increase the likelihood of secondary amplification. These findings support the idea that spatial clustering of mosquitoes and birds may facilitate arbovirus amplification. This model provides a basis for future exploration of specific zoonotic transmission cycles, including West Nile virus, and could be used to test the efficacy of various control strategies.     

Spatial analysis of Percutaneous Transluminal Coronary Angioplasty (PTCA) in Austria

Study objectives: To investigate the geographical distribution of Percutaneous Transluminal Coronary Angioplasty (PTCA) and morbidity for coronary heart disease, angina pectoris and myocardial infarction by spatial analysis of the standardized morbidity rates (SMR) on district level. To identify clusters by Moran's I Statistic and the Regional Spatial Autocorrelation Coefficient (RSAC) of Munasinghe and Morris. To investigate demand factor morbidity and supply factor health care infrastructure on the district level as reasons for geographical disparity. To describe characteristics of the cluster population and intervention centres. Study design: Retrospective record linkage study. Setting: All hospitals and cardiological centres in Austria (n = 150) which performed the Minimum Basic Data Set (MBDS). Patients: All Austrian residents who were diagnosed for myocardial infarction, coronary heart disease or angina pectoris in 1995 (n = 87,174). Measurements and main results: One positive PTCA cluster (all SMRs 0.96) and one negative PTCA cluster (all SMRs 0.59) were identified. They differed significantly in morbidity rate, intervention rate and available cardiological beds. The tendency to inverse relation between PTCA utilization and morbidity in the negative cluster supported the thesis of inverse care law. Austrianwide no significant correlation was found between the SMR of PTCA-application and both demand factor and supply factors. Nevertheless, differences between the clusters concerning number and capacity of intervention centres and density of specialists pointed to supply factors as reasons for geographical disparity. The ongoing trend of steady expansion of existing intervention centres and establishment of new ones will reduce the extent of geographical variation in future.     

骨痹病近现代中医外治方药文献研究

目的:通过文献检索,分析近现代中医外治方药治疗骨痹病的药物组成特点,探讨并归纳其方药特点与遣方用药规律。方法:以近现代医家论治骨痹的医案、方书、骨伤专著及核心学术期刊等为收集对象,采用电子检索和手工检索的方法对上述文献进行查录,对近现代文献中查录的170首骨痹病外治方药的组成及用药规律进行分析与总结。结果:骨痹病外治方药中补虚药、活血化瘀药、祛风湿药的应用最为常见;其中以草乌、川乌、当归、细辛、独活、红花、没药、乳香、威灵仙、透骨草等药物的使用频率最高,对常用高频药物进行聚类分析后得到8个药物组方及常用药对。结论:通过对近现代骨痹病外治方药药物组织及组方规律的研究与分析,佐证了近现代医家对骨痹病本质(虚、邪、瘀)的认识,从而在本病的治法治则和外治方药的组方用药规律上分别体现了相应的特点,对骨痹病外治方药的现代化研究有着重要的指导意义。     

青海省恙螨聚类分析的探讨

目的研究青海省恙螨区系分布特点,结合聚类结果初步探讨青海恙螨地理分布格局。方法用层次聚类分析方法。结果青海省恙螨可聚为2大类群,青海羌塘高原和果洛玉树高原的恙螨在距离系数0.007的水平上聚为1个新类群,柴达木盆地、青海祁连山地、黄南山地、湟水河谷的恙螨在0.155水平聚为1个新类群。结论青海恙螨分布虽然在不同地理单元且具有混杂和相互渗透的现象,但可以将青海省恙螨分为2大类群。     

顺铂化疗对口腔颌面部鳞癌细胞基因表达谱的影响

目的 探讨口腔颌面部鳞癌对顺铂的应答规律，以阐明肿瘤耐药的作用机制，指导临床化疗。方法 收集(8例)4对临床标本，根据其是否接受过顺铂化疗，分为2组，采用Affymetrix HG—U95Av2寡核苷酸芯片对其基因表达谱进行聚类分析。结果 应用Genespring软件同时对标本和基因进行聚类，发现根据标本是否接受过顺铂化疗及化疗效果可正确聚类，而且利用基因聚类的结果，筛选出关系最密切的50条基因，其表达情况能够正确预测标本是否接受过顺铂化疗。结论 顺铂化疗可改变一组基因在口腔鳞癌的表达，可以通过该组基因的表达谱对标本进行正确聚类．而且这种改变可能与口腔鳞癌顺铂化疗效果相关。     

应用HITS算法对文本聚类结果进行类别描述的可行性分析

介绍HITS算法的基本思想和执行方法,提取出聚类结果中每一类的特征词,基于HITS算法客观地描述聚类分析结果,分析其可行性并进行应用尝试。实践证明利用该算法进行聚类结果特征提取切实可行。     

BARTMAP: A viable structure for biclustering

Clustering has been used extensively in the analysis of high-throughput messenger RNA (mRNA) expression profiling with microarrays. Furthermore, clustering has proven elemental in microRNA expression profiling, which demonstrates enormous promise in the areas of cancer diagnosis and treatment, gene function identification, therapy development and drug testing, and genetic regulatory network inference. However, such a practice is inherently limited due to the existence of many uncorrelated genes with respect to sample or condition clustering, or many unrelated samples or conditions with respect to gene clustering. Biclustering offers a solution to such problems by performing simultaneous clustering on both dimensions, or automatically integrating feature selection to clustering without any prior information, so that the relations of clusters of genes (generally, features) and clusters of samples or conditions (data objects) are established. However, the NP-complete computational complexity raises a great challenge to computational methods for identifying such local relations. Here, we propose and demonstrate that a neural-based classifier, ARTMAP, can be modified to perform biclustering in an efficient way, leading to a biclustering algorithm called Biclustering ARTMAP (BARTMAP). Experimental results on multiple human cancer data sets show that BARTMAP can achieve clustering structures with higher qualities than those achieved with other commonly used biclustering or clustering algorithms, and with fast run times.     

Data-driven clustering reveals a fundamental subdivision of the human cortex into two global systems

Global organizational principles are critical for understanding cortical functionality. Recently, we proposed a global sub-division of the posterior cortex into two large-scale systems. One system, labeled extrinsic, comprises the sensory-motor cortex, and is associated with the external environment. The second system, labeled intrinsic, overlaps substantially with the previously described "default-mode" network, and is likely associated with inner-oriented processing. This global partition of the cerebral cortex emerged from hemodynamic imaging data the analysis of which was constrained by pre-determined hypotheses. Here we applied a hypothesis-free, unsupervised two-class clustering algorithm (k-means) to a large set of fMRI data. The two clusters delineated by this unsupervised hypothesis-free procedure showed high anatomical consistency across individuals, and their cortical topography coincided largely with the previously determined extrinsic and intrinsic systems. These new clustering-based results confirm that the intrinsic-extrinsic subdivision constitutes a fundamental cortical divide.     

亚健康人群分类及其临床特征分析与评价——基于数据挖掘流程的Logistic回归方法的研究

目的:本文应用基于数据挖掘流程的logistic回归方法建模,对亚健康状态的人群进行分类并分析其临床特征。方法:针对亚健康状态流行病学调查数据进行统计分析,采用从数据理解、数据准备、变量筛选和选择logistic回归建模的数据挖掘流程的方法,确定最终的回归方程,从而得到亚健康状态的判别方程及其临床特征。结果:建立了两种logistie回归模型,并在此基础上应用数据挖掘的思想对回归方程做进一步的测试,得到了分类准确率较高的验证,其结果提示亚健康的主要临床特征表现为躯体的疲劳、睡眠不实、记忆力和工作效率下降、饮食二便失调、心理的空虚感和情绪易怒等。结论:在分析判断和解释影响因素较复杂、自变量较多的亚健康人群临床特征研究中,使用传统意义的logistic回归建模具有很大的优越性。