A String Matching Computer-Assisted System for Dolphin Photoidentification

This paper presents a syntactic/semantic string representation scheme as well as a string matching method as part of a computer-assisted system to identify dolphins from photographs of their dorsal fins. A low-level string representation is constructed from the curvature function of a dolphin's fin trailing edge, consisting of positive and negative curvature primitives. A high-level string representation is then built over the low-level string via merging appropriate groupings of primitives in order to have a less sensitive representation to curvature fluctuations or noise. A family of syntactic/semantic distance measures between two strings is introduced. A composite distance measure is then defined and used as a dissimilarity measure for database search, highlighting both the syntax (structure or sequence) and semantic (attribute or feature) differences. The syntax consists of an ordered sequence of significant protrusions and intrusions on the edge, while the semantics consist of seven attributes extracted from the edge and its curvature function. The matching results are reported for a database of 624 images corresponding to 164 individual dolphins. The identification results indicate that the developed string matching method performs better than the previous matching methods including dorsal ratio, curvature, and curve matching. The developed computer-assisted system can help marine mammalogists in their identification of dolphins, since it allows them to examine only a handful of candidate images instead of the currently used manual searching of the entire database. © 2000 Biomedical Engineering Society. PAC00: 8780Tq, 4230Sy, 0705Pj     

中医药学语言系统中语义类型的语境分析

目的:主题词表是可扩充的动态性叙词表,文献中的主题词标引具有很好的语义环境。因此,文章尝试从主题词集合的角度对中医药学语言系统(TCMLS)中的语义类型进行扩展研究。方法:对3515篇有关"腧穴"临床文献进行主题词的语义类型提取,采用聚类分析将语义类型聚成4个分类,组成一个大语境模板。结果:实验结果证明采用聚类分析得到的语义类型的语境模板,比较符合临床文献实际。该方法对TCMLS语义类型的加工和检索具有提示作用,是一个值得尝试的研究工作。     

基于“药性—功效知识元语义分析”探讨四气中的“平性”

四气,又称四性,即指药物具有的寒热温凉四种药性。四性之外,还有平性,是指药物寒热偏性不明显者,但有学者认为这只是相对而言,实际上仍有偏温偏凉之别,仍未超出四气范围。既然未超出寒热范围,那么为什么提出平性,并沿用至今呢?平性,到底有什么独特的之处呢?以2005年版《中国药典》所载的性、味、归经、齐全523味药物为研究对象,尝试基于药性—功效知识元语义分析,探讨平性的药性定位,并与"寒、凉、温、热"四性进行比较,从而论述"平"性与四气中其他四性的关系。     

Re-visiting "semantic facilitation" of word retrieval for people with aphasia: facilitation yes but semantic no

Previous research has shown that word-to-picture matching for targets that cannot be named at pre-test results in improved naming relative to untreated control items for people with aphasia. This paper replicates and extends this finding and investigates its source. Is the effect a result of priming of semantic representations, or of post-semantic mechanisms in word retrieval? The first experiment shows that word-to-picture matching with unrelated distractors improves naming at short (2-3 minutes) and long (up to 25 minute) lags. There was no effect of being made aware of the relationship between word-to-picture matching and picture naming. People who have a semantic impairment improve only with a short lag between word-to-picture matching and naming. Participants with less semantic impairment show larger priming effects that are equal at short and long lags between word-to-picture matching and naming. The second experiment shows that the facilitation effect is just as large for word-to-picture matching with unrelated distractors as with semantically-related distractors. Furthermore, overall there was no difference between matching with coordinate items and with associated items. The results of these experiments show that facilitation of naming by word-to-picture matching in people with aphasia cannot be a result of the priming of semantic representations. Instead they are consistent with two effects: word-to-picture matching results in priming at a lemma level for aphasic people with a semantic impairment that is only found with a short lag between word-to-picture matching and naming. Word-to-picture matching causes priming of the lemma to output lexicon entry mapping that benefits participants with less semantic impairment that is evident at both a short and long lag between word-to-picture matching and naming. These findings fit well with previous research on repetition priming of naming with normal subjects.     

雌激素水平下降对记忆的影响

目的:探讨雌激素水平急剧下降对记忆和各记忆成分的影响.方法:对两侧卵巢切除患者的记忆和雌激素水平进行检查,并与有相似手术史但卵巢功能保留的患者进行比较,两组患者年龄、文化程度及手术年限相匹配,采用WMS测查记忆的同时测定血清雌激素水平E2.结果:两侧卵巢全切除组与卵巢保留组相比记忆差异没有统计学意义(P＞0.05),各记忆成分卵巢全切除组除定向记忆明显差外(P＜0.05),两组患者的各项记忆成分测验差异均无显著性(P＜0.05).经相关性分析发现:雌激素水平与记忆商、联想记忆、背数、言语记忆和数字记忆呈明显正相关(P＜0.05).结论:雌激素对记忆的影响能力是有限的,雌激素主要影响言语记忆和数字记忆,而不是记忆的全过程.     

用近红外功能成像技术研究语义和知觉编码过程中左前额叶的活动

目的用近红外光学功能成像技术研究语义与知觉编码过程中的左前额叶活动.方法实时记录22名青年被试者(男女各半)在语义和知觉加工过程中760 nm和850 nm两个波长近红外连续光透过额骨和左前额皮层后的漫射光强变化,并以此表征该皮层区血容(CBV)和血氧的变化.语义加工要求被试者用两个非相关的汉字词对组成一个有意义的句子;知觉加工则要求被试者判断两个词是否具有相同的结构组合以及两个词对中左右结构的差别. 结果结果显示,与知觉加工相比,语义加工时左下前额叶活动增多.该区域大致对应布德曼45、47区的一部分. 结论成功地利用近红外功能成像技术观测了语义与知觉编码过程中的左前额叶活动,获得了与fMRI和断层成象技术(PET)研究相近的结果,进一步证实了左前额叶在语义加工中的作用.     

Changing perceptions of self as a communicator in Parkinson's disease: a longitudinal follow-up study

Purpose.?Dysarthria in neurological conditions can impact on people's view of themselves as communicators. How views might evolve and how they relate to changes in other variables remains unclear. We investigated patterns of change in self-perception as a communicator in people with Parkinson's disease (PD) and compared outcomes to changes in other clinical measures.

Methods.?Thirty-one people with initially early-stage PD completed a 22-item self-administered semantic differential questionnaire aimed at characterising their view of themselves as communicators before they had PD and at two assessment points 3 years apart. Patterns of change across time were analysed, and compared to intelligibility, motor, mood and cognitive measures.

Results.?Negative changes in perceptions of self as a communicator occurred, in particular in reactions around competence, adequacy, control and ease in communication. There was variability between individuals and between items. No significant relationship was established between changes on self-perception scores and other measures.

Conclusions.?Individuals' views of themselves as communicators evolve over time in progressive neurological conditions. Changes do not relate straightforwardly to other clinical measures. Major impact can occur despite good intelligibility levels. Exploring self-perceptions, individual reactions and coping strategies are argued to be a vital part of assessment and management.     

轻度认知功能损害患者汉语双词素词的语音编码研究

目的探讨轻度认知功能损害 (MCI)患者汉语言语产生中双词素词语音激活的特点。方法对 10例MCI患者和 10例正常对照采用同音判断方法 ,选用以偏正结构的双词素词为名称的图片和与双词素词中首尾两个词素同音的两组探测字作为实验材料 ,探测字在图片呈现后 10 0ms出现 ,要求被试判断出现的探测字是否与图片名称中任何一个词素同音。对两组的反应时和错误率进行比较。结果正常老年人尾词素激活快于首词素激活 ,而MCI患者首尾词素激活时间无明显差异。首尾词素探测条件下正常老年人反应的错误率无明显差异 ,而MCI患者对尾词素探测条件的错误率低于首词素。结论正常老年人和MCI患者汉语言语产生中双词素词语音编码模式相同 ,均受词义和词素意义激活程度的影响 ;但激活的速度MCI患者慢于正常老年人。提示MCI患者语义记忆和语音提取的过程受损。     

Neuroimaging in dementia

Over the last few years, advances in neuroimaging have generated biomarkers, which increase diagnostic certainty, provide valuable information about prognosis, and suggest a particular pathology underlying the clinical dementia syndrome. We aim to review the evidence for use of already established imaging modalities, along with selected techniques that have a great potential to guide clinical decisions in the future. We discuss structural, functional and molecular imaging, focusing on the most common dementias: Alzheimer's disease, fronto-temporal dementia, dementia with Lewy bodies and vascular dementia. Finally, we stress the importance of conducting research using representative cohorts and in a naturalistic set up, in order to build a strong evidence base for translating imaging methods for a National Health Service. If we assess a broad range of patients referred to memory clinic with a variety of imaging modalities, we will make a step towards accumulating robust evidence and ultimately closing the gap between the dramatic advances in neurosciences and meaningful clinical applications for the maximum benefit of our patients.