中医药文献语义标注系统研究与开发

目的研究和开发支持中医和现代生物医学本体和术语集的语义标注系统。方法以MedPortal本体库和中医临床术语集等为术语资源库,设计语义标注系统工作流程和功能框架,并开发Web应用系统。结果构建了一个基于Web的中医药文献语义标注系统,支持语料库管理与维护、术语词典管理、语义标注和语义检索等功能,既可以为基于机器学习的信息抽取算法研究提供训练集,又能实现语义层面的多来源数据集成与知识融合。结论该中医药文献语义标注系统设计方案已经过实际项目验证,可为其他同类系统研发提供参考。     

Semantic category and initial letter word fluency in left-brain-damaged patients

Fluency deficits have been found in different neuropsychological populations, and dissociation of letter initial and category fluency has been demonstrated in right-brain-damaged and Alzheimer patients. Studies on normal controls also indicate that letter initial and category fluency are supported by different brain regions. We studied letter initial and category fluency in 79 left-brain-damaged patients, 18 non-aphasic and 61 aphasic. Our results indicate that brain-damaged patients are significantly impaired in both fluency tasks compared to normal controls, and a difference between letter initial and category fluency emerges from our data. Firstly, only letter initial fluency is more impaired in aphasic than in non-aphasic patients; secondly, many aphasics have normal category fluency and pathological letter initial fluency but the reverse is seldom true and thirdly, only category fluency scores correlate with confrontation-naming scores. It is suggested that strategies to recover words based on a semantic or a phonological prompt are different. A semantic strategy is coherent with the organizational structure of the semantic system and corresponds to the normal way in which we recover words whereas a phonological strategy is quite unusual and it is not used for actual communication.     

Alternative graphical representations of genotypes in a pedigree

Three representations of the conditional independences due toMendelian segregation of genes in a pedigree are proposed. Thecomputational costs of performing calculations using the techniqueof peeling with each of these representations is compared byconsidering the weights of triangulations of the graph producedby each representation.     

Memory function in normal aging

Basic findings obtained on memory functions in normal aging are presented and discussed with respect to five separate but interacting memory systems. These systems are: episodic memory, semantic memory, short-term memory, perceptual representation system and procedural memory. All available evidence from cross-sectional research shows that there is a linear, decreasing memory performance as a function of age for episodic memory. Longitudinal studies suggest, however, that this age deficit may be an overestimation, by showing a relatively stable performance level up to middle age, followed by a sharp decline. Studies on semantic memory, short-term memory, perceptual representation system, and procedural memory show a relatively constant performance level across the adult life span, although some tasks used to assess short-term memory and procedural memory have revealed an age deficit. Disregarding the mixed results for these latter two memory systems, it can be concluded that episodic memory is unique in showing an age deficit. Episodic memory is also unique in the sense that it is the only memory system showing gender differences in performance throughout the adult life span with a significantly higher performance for women.     

Simulating realistic zero loop pedigrees using a bipartite Prufer code and graphical modelling.

Graph algorithms previously developed by the authors are adapted to simulate pedigrees similar to those used in genetic linkage studies which associate disease phenotypes with specific genomic locations. Pedigrees are chosen uniformly at random from the set of those with specified numbers of individuals and matings and which contain no loops. Summary statistics from pedigrees generated in this way can be used to check real pedigrees for anomalies due to biased sampling or phenotypic effects on the pedigree structure.     

睡眠剥夺对内隐记忆的影响

目的:探讨不同时间睡眠剥夺(sleep deprivation,SD)对内隐记忆的影响。方法:将32名青年男性随机分为4组:对照组、SD21、SD45和SD69组,每组8名。采用补笔测验和组词测验对4组被试进行测试。结果:SD 后无论知觉启动还是语义启动,启动量降低,并随SD 时间延长而减少。同一组内,两种测验进行比较,除对照组外,其他SD 组两两比较,语义启动的启动量大于知觉启动(P<0.05)。知觉启动中,SD45同SD69 相比无显著差异(P=0.245),其他两两比较差异均有统计学意义(P<0.01);语义启动中,SD21同对照组相比差异无统计学意义(P=0.316),其他两两比较差异均有统计学意义(P<0.01)。结论:SD 后内隐记忆受损,并同SD 时间有关;SD 后语义启动和知觉启动出现分离,知觉启动更受SD 影响。     

Repetition and semantic priming of nonwords: implications for theories of N400 and word recognition

ERPs were elicited by two types of orthographically legal, pronounceable nonwords. One nonword set was derived from and resembled real words, whereas the other set did not. Nonwords derived from related root words elicited N400 semantic priming effects similar to those obtained for words, indicating semantic activation of the root words. N400 repetition priming effects from nonderived nonwords were similar to those obtained for words. The elicitation of N400 by only derived nonwords would have suggested it was generated by the activation of word meanings, per se. However, both types of nonwords produced an N400, and an N400 priming effect. Because nonderived nonwords are not associated with meaning, the N400 cannot be generated by semantic activation per se. Rather, the N400 appears to be generated by orthographic/phonological analysis and is attenuated by the top-down feed of semantic information to the orthographic/phonological level.     

Electrocortical signs of word categorization in saccade-related brain potentials and visual evoked potentials

Visual evoked potentials (VEPs) elicited by foveal presentation of words were compared to brain potentials evoked by the same words in a condition where subjects had to make a saccadic eye movement in order to perceive the words (saccade-related brain potentials, SRPs). Subjects had to categorize the words responding with a button press to stimuli belonging to the target (infrequent, P = 0.2) category. The VEP and SRP waveforms showed divergences in the early (up to 250 ms) components, but a marked similarity between the late components. Principal Component Analysis also revealed the same relationship between the two types of brain responses. Peak latency of the late SRP components measured from saccade offset showed an apparent processing advantage over the corresponding late components of VEPs. The N3 component, indexing semantic processing of visual patterns, peaked between 310 and 375 ms in the SRPs, while in the VEPs it appeared between 410 and 470 ms. The P4 component, associated with final stimulus evaluation, showed a similar latency benefit in favour of SRPs (420-500 ms vs 530-590 ms in VEPs). The mean reaction time was 74 ms shorter in the eye movement condition (measured from saccade offset) than in the VEP condition (703 vs 777 ms). The question of what kind of processes may contribute to the differences in mean RTs and to the latencies of the late components between the two conditions are discussed. We suggest that the late components (P3, N3 and P4) of the VEP and the SRP, respectively, index identical brain processes.