首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
X-ray and morphological signs were compared in 50 patients with histologically verified bronchioloalveolar cancer (BAC). Particular attention was drawn to a study of an x-ray picture after computer processing of a tomographic image using a special technique. The most characteristic x-ray signs of BAC were subpleural localization, the presence of a fragmented scar in a tumor, and ill defined outlines. The peculiarities of an x-ray picture of small-size BAC were determined by the morphological structure of a tumor, a degree of its differentiation that could be detected in most cases only after image processing by the linear filtration technique.  相似文献   

2.
How pictures and words are stored and processed in the human brain constitute a long-standing question in cognitive psychology. Behavioral studies have yielded a large amount of data addressing this issue. Generally speaking, these data show that there are some interactions between the semantic processing of pictures and words. However, behavioral methods can provide only limited insight into certain findings. Fortunately, Event-Related Potential (ERP) provides on-line cues about the temporal nature of cognitive processes and contributes to the exploration of their neural substrates. ERPs have been used in order to better understand semantic processing of words and pictures. The main objective of this article is to offer an overview of the electrophysiologic bases of semantic processing of words and pictures. Studies presented in this article showed that the processing of words is associated with an N 400 component, whereas pictures elicited both N 300 and N 400 components. Topographical analysis of the N 400 distribution over the scalp is compatible with the idea that both image-mediated concrete words and pictures access an amodal semantic system. However, given the distinctive N 300 patterns, observed only during picture processing, it appears that picture and word processing rely upon distinct neuronal networks, even if they end up activating more or less similar semantic representations.  相似文献   

3.
Inhomogeneous and anisotropic processing stages developed in the visual system during evolution in order to match a (certainly highly complex) biological optimality criterion. As the examples presented in this paper show, scenes viewed can be separated stages such as processing of the central area of the picture field in a wide band fashion, where each detail is percieved and the contrasts are amplified. This requires good illumination as the amplification is small. At the periphery the amplification is higher which favors twilight vision. Especially the sensitivity for moving patterns is highly developed and a band pass prefilter requires only spatially narrow band channels in the course of further processing. Direction specific filter stages make it possible to solve special problems such as the reconstruction of a form from an illuminance distribution.  相似文献   

4.
Baccus SA 《Neuron》2006,51(6):682-684
In this issue of Neuron, Nagel and Doupe make a quantitative assessment of temporal adaptation in the avian auditory forebrain, capturing seemingly complex responses with a simple linear-nonlinear (LN) model of kinetics and gain. A comparison of these findings with similar results in the early visual system shows an important unifying picture of efficient sensory processing and adaptation.  相似文献   

5.
The differentiation of the thyroid glands follicular neoplasias into adenomas and carcinomas is currently done using the histological criteria recommended by WHO. This pilot study of 10 human follicular carcinomas and 10 folliculars adenomas demonstrates the possibility of a cytological classification using digital picture processing of high resolution cell images. Giemsa stained paraplast sections were scanned with a Colour-TV-camera, different channels were used with respect to staining and analyzing methods and computed with an image processing system. The computer aided cytophotometric methods detected significant differences in the chromatin arrangement and structure.  相似文献   

6.
Findlay JM 《Spatial Vision》2008,21(3-5):271-272
The Fisherman, a picture painted by Jean-Louis Forain, demonstrates an interesting interaction between low and high level perceptual processing. The isolation and tranquillity of the fisherman in the picture are enhanced by the absence of his reflection, yet perceivers are rarely aware of the omission.  相似文献   

7.
The ''Positive Effect'' is defined as the phenomenon of preferential cognitive processing of positive affective information, and avoidance or dismissal of negative affective information in the social environment. The ‘Positive Effect’ is found for older people compared with younger people in western societies and is believed to reflect a preference for positive emotional regulation in older adults. It is not known whether such an effect is Universal, and in East Asian cultures, there is a highly controversial debate concerning this question. In the current experiment we explored whether Chinese older participants showed a ''Positive Effect'' when they inspected picture pairs that were either a positive or a negative picture presented with a neutral picture, or a positive and negative picture paired together. The results indicated that both groups of participants showed an attentional bias to both pleasant (more processing of) and unpleasant pictures (initial orienting to) when these were paired with neutral pictures. When pleasant and unpleasant pictures were paired together both groups showed an initial orientation bias for the pleasant picture, but the older participants showed this bias for initial orienting and increased processing measures, providing evidence of a ‘Positive Effect’ in older Chinese adults.  相似文献   

8.
Recent work has questioned whether the negativity bias is a distinct component of affective picture processing. The current study was designed to determine whether there are different neural correlates of processing positive and negative pictures using event-related brain potentials. The early posterior negativity and late positive potential were greatest in amplitude for erotic pictures. Partial Least Squares analysis revealed one latent variable that distinguished erotic pictures from neutral and positive pictures and another that differentiated negative pictures from neutral and positive pictures. The effects of orienting task on the neural correlates of processing negative and erotic pictures indicate that affective picture processing is sensitive to both stimulus-driven, and attentional or decision processes. The current data, together with other recent findings from our laboratory, lead to the suggestion that there are distinct neural correlates of processing negative and positive stimuli during affective picture processing.  相似文献   

9.
10.
Additional information on an x-ray picture of peribronchial changes in tumorous and non-tumorous lesions of the lungs were obtained in 54 patients (40 with bronchogenic, mostly central cancer and 14 with chronic inflammatory diseases) in order to study roentgenological symptomatology before and after computerized processing of tomographic images using a method of linear filtration. Image processing with the measurement of densitometric indicators provides additional information for the estimation of bronchial affection by tumor infiltration. The same method can be of value for the detection of early signs of lung cancer in patients with peribronchial changes of obscure etiology.  相似文献   

11.
目的研讨透视图像亮度自动控制应用的三种剂量率调整方法。方法自动调整毫安值、自动调整仟伏值、自动调整毫安和仟伏值。结果有助于保持最佳透视图像成像质量,提高临床诊断效率。结论采用自动仟伏调整和自动毫安、仟伏调整不失为行之有效的方法  相似文献   

12.
Many models of object identification are bottom-up and serial in nature; processing at a first stage needs to be complete before it is passed on to a subsequent stage, and there is no top-down feedback from the later to the earlier stages. However, data on picture identification in normal observers contradict a strict serial account of processing, since effects of variables on early and late stages of object identification combine in an interactive rather than an additive manner. Recent neuropsychological and functional anatomical data also indicate that object identification involves top-down activation of earlier stages of visual processing. In neuropsychological patients, subtle perceptual deficits can produce naming problems, even when there is good access to associated semantic knowledge; in functional activation studies, there is increased activity in visual processing areas when conditions require object naming relative to object recognition. These studies provide evidence that increased visual processing occurs in identification tasks, suggesting that there is re-current feedback during the identification process.  相似文献   

13.
The use of pictures to illustrate science text is not usually taken to be problematic. However, the ‘picture superiority effect’ (PSE), whereby pictures are deemed to enhance learning from text, has been examined systematically over the last decade and has been found to be more equivocal than was hitherto believed. Part 1 of this review of the PSE in learning biology examines a number of perceptual considerations that need to be given to picture construction. It examines the major parameters which appear to attract the learner's attention to the picture in the first place, and then directs their subsequent viewing. These parameters are important because they exert control over the information the learner extracts from the picture. They are also important because, once recognized, it should be possible to control their influence in such a way as to optimize learning. These parameters fall into two main categories: those residing within the picture itself (for example, figure-ground differentiation) and those within the learner (for example, cultural bias). The review discusses ways in which within-picture variables such as depth of field and colour can be manipulated to re-inforce the intended message. It also suggests that more explicit instructions need to be given to learners to guide their use of texts with picture adjuncts. The importance of teaching children how to read pictures is complicated by the ways in which picture and text interact in the mind of the learner, and future comment on this aspect of the learning process is deferred to Part 2 of the article, which deals specifically with aspects of picture-text processing.  相似文献   

14.
Experience plays a crucial role in the development of the face processing system. At 6 months of age infants can discriminate individual faces from their own and other races. By 9 months of age this ability to process other-race faces is typically lost, due to minimal experience with other-race faces, and vast exposure to own-race faces, for which infants come to manifest expertise [1]. This is known as the Other Race Effect. In the current study, we demonstrate that exposing Caucasian infants to Chinese faces through perceptual training via picture books for a total of one hour between 6 and 9 months allows Caucasian infants to maintain the ability to discriminate Chinese faces at 9 months of age. The development of the processing of face race can be modified by training, highlighting the importance of early experience in shaping the face representation.  相似文献   

15.
Neuroscientific investigations regarding aspects of emotional experiences usually focus on one stimulus modality (e.g., pictorial or verbal). Similarities and differences in the processing between the different modalities have rarely been studied directly. The comparison of verbal and pictorial emotional stimuli often reveals a processing advantage of emotional pictures in terms of larger or more pronounced emotion effects evoked by pictorial stimuli. In this study, we examined whether this picture advantage refers to general processing differences or whether it might partly be attributed to differences in visual complexity between pictures and words. We first developed a new stimulus database comprising valence and arousal ratings for more than 200 concrete objects representable in different modalities including different levels of complexity: words, phrases, pictograms, and photographs. Using fMRI we then studied the neural correlates of the processing of these emotional stimuli in a valence judgment task, in which the stimulus material was controlled for differences in emotional arousal. No superiority for the pictorial stimuli was found in terms of emotional information processing with differences between modalities being revealed mainly in perceptual processing regions. While visual complexity might partly account for previously found differences in emotional stimulus processing, the main existing processing differences are probably due to enhanced processing in modality specific perceptual regions. We would suggest that both pictures and words elicit emotional responses with no general superiority for either stimulus modality, while emotional responses to pictures are modulated by perceptual stimulus features, such as picture complexity.  相似文献   

16.
李辉  李华  苏俊红  倪文  曹辉 《生物磁学》2011,(16):3120-3122,3182
目的:探讨卒中后失语患者高级语言认知功能的改变。方法:利用事件相关电位N400探讨15例脑卒中后失语患者(观察组)及15例正常人(对照组)图片一词语语义一致(匹配)与语义不一致(不匹配)时的语言加工过程。结果:与对照组相比脑卒中后失语患者N400潜伏期有统计学差异,但相关性分析N400的波幅没有统计学差异。结论:1.卒中后失语患者存在语言加工过程的延迟2.额叶以及顶叶可能在语义生成的过程中起重要作用3.是否能将认知电位N400作为评估卒中后语言障碍的一项指标还有待进一步探讨。  相似文献   

17.
When evaluating functional relationships from given data in an exploratory state of investigation, we only want to get an imagination of a possibly existing trend. Usually, methods of local or empirical regression are chosen to meet this purpose. In the paper we suggest an alternative using the possibilities of modern picture processing methods and computers. The data were transformed into a grey-tone picture representing a fuzzy observation set, the maximum trace of which yields the desired first impression of the trend and may serve as the starting point for further detailed evaluation of the functional relationship. The method is illustrated by a real-data numerical example.  相似文献   

18.
The last 10 years have seen the rise of many technologies that produce an unprecedented amount of genome-scale data from many organisms. Although the research community has been successful in exploring these data, many challenges still persist. One of them is the effective integration of such data sets directly into approaches based on mathematical modeling of biological systems. Applications in cancer are a good example. The bridge between information and modeling in cancer can be achieved by two major types of complementary strategies. First, there is a bottom-up approach, in which data generates information about structure and relationship between components of a given system. In addition, there is a top-down approach, where cybernetic and systems-theoretical knowledge are used to create models that describe mechanisms and dynamics of the system. These approaches can also be linked to yield multi-scale models combining detailed mechanism and wide biological scope. Here we give an overall picture of this field and discuss possible strategies to approach the major challenges ahead.  相似文献   

19.
In bulk heterojunction (BHJ) polymeric organic solar cells (OSCs), the use of processing additives in the material formulation has emerged as a promising, cost‐effective, and widely applicable method for optimizing the phase separation between the donor (D) and acceptor (A) materials, thus increasing their efficiency. So far, however, there has been no systematic approach for identifying suitable processing additives for a given D:A system. A method based on the Hansen solubility parameters (HSPs) is proposed for guiding the selection of processing additives for a given D:A combination. The method is applied to the archetypical poly(3‐hexylthiophene) (P3HT) and [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) system. The HSPs of these materials are determined and used to define a set of numerical criteria that need to be satisfied by a processing additive in order for it to be effective in realizing a higher efficiency OSC. Applying the selection criteria results in the identification of three novel processing additives. OSCs made of these formulations demonstrate an increase in their short‐circuit current density (JSC) and power conversion efficiency (PCE). These results demonstrate the efficiency of these novel processing additives and show that the HSPs represent a useful tool to determine and explore new types of processing additives for BHJ‐OSCs.  相似文献   

20.
Origin, targeting, and function of the apicomplexan plastid.   总被引:1,自引:0,他引:1  
The discovery of a plastid in Plasmodium, Toxoplasma and related protozoan parasites provides a satisfying resolution to several long-standing mysteries: the mechanism of action for various surprisingly effective antibiotics; the subcellular location of an enigmatic 35 kb episomal DNA; and the nature of an unusual intracellular structure containing multiple membranes. The apicomplexan plastid highlights the importance of lateral genetic transfer in evolution and provides an accessible system for the investigation of protein targeting to secondary endosymbiotic organelles. Combining molecular genetic identification of targeting signals with whole genome analysis promises to yield a complete picture of organellar metabolic pathways and new targets for drug design.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号