排序方式： 共有43条查询结果，搜索用时 0 毫秒
41.
探讨B超配合在麦默通微创行乳腺良性肿块切除术中的作用。对569例乳腺肿块进行麦默通微创切除术,分别于术前进行B超定位,术中进行B超引导,术后B超探查及随访,分析B超配合对手术的彻底性、安全性和准确性等所起的作用与意义。结果569例患者的乳腺病灶均被准确切除,B超熟练程度决定手术的准确性、彻底性及手术时间。术中B超配合20次以上者,其一次定位成功并一次完全切除率达87.4%,与初次(B超配合20次以下)配合者相比,两者有显著性差异(P=0.000);手术时间亦比初次B超配合者要短,两者有显著性差异(P=0.000)。熟练的B超配合,有利于麦默通微创旋切技术准确、有效、快速而安全的切除乳腺良性肿瘤。 相似文献
42.
Cognitive systems face a tension between stability and plasticity. The maintenance of long-term representations that reflect the global regularities of the environment is often at odds with pressure to flexibly adjust to short-term input regularities that may deviate from the norm. This tension is abundantly clear in speech communication when talkers with accents or dialects produce input that deviates from a listener's language community norms. Prior research demonstrates that when bottom-up acoustic information or top-down word knowledge is available to disambiguate speech input, there is short-term adaptive plasticity such that subsequent speech perception is shifted even in the absence of the disambiguating information. Although such effects are well-documented, it is not yet known whether bottom-up and top-down resolution of ambiguity may operate through common processes, or how these information sources may interact in guiding the adaptive plasticity of speech perception. The present study investigates the joint contributions of bottom-up information from the acoustic signal and top-down information from lexical knowledge in the adaptive plasticity of speech categorization according to short-term input regularities. The results implicate speech category activation, whether from top-down or bottom-up sources, in driving rapid adjustment of listeners' reliance on acoustic dimensions in speech categorization. Broadly, this pattern of perception is consistent with dynamic mapping of input to category representations that is flexibly tuned according to interactive processing accommodating both lexical knowledge and idiosyncrasies of the acoustic input. 相似文献
43.
John E. Kiat Steven J. Luck Aaron G. Beckner Taylor R. Hayes Katherine I. Pomaranski John M. Henderson Lisa M. Oakes 《Developmental science》2022,25(1):e13155
Little is known about the development of higher-level areas of visual cortex during infancy, and even less is known about how the development of visually guided behavior is related to the different levels of the cortical processing hierarchy. As a first step toward filling these gaps, we used representational similarity analysis (RSA) to assess links between gaze patterns and a neural network model that captures key properties of the ventral visual processing stream. We recorded the eye movements of 4- to 12-month-old infants (N = 54) as they viewed photographs of scenes. For each infant, we calculated the similarity of the gaze patterns for each pair of photographs. We also analyzed the images using a convolutional neural network model in which the successive layers correspond approximately to the sequence of areas along the ventral stream. For each layer of the network, we calculated the similarity of the activation patterns for each pair of photographs, which was then compared with the infant gaze data. We found that the network layers corresponding to lower-level areas of visual cortex accounted for gaze patterns better in younger infants than in older infants, whereas the network layers corresponding to higher-level areas of visual cortex accounted for gaze patterns better in older infants than in younger infants. Thus, between 4 and 12 months, gaze becomes increasingly controlled by more abstract, higher-level representations. These results also demonstrate the feasibility of using RSA to link infant gaze behavior to neural network models. A video abstract of this article can be viewed at https://youtu.be/K5mF2Rw98Is 相似文献