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81.
To explore the enterprise credit risk evaluation, the application effect of several common neural network models in Chinese small and medium-sized enterprise data sets was compared and the optimal parameters for each model were determined. In addition, the classification accuracy and the applicability of the model were compared, and finally the common problem of optimization neural network algorithm based on population was solved: need to determine the dimensions in advance. The experimental results showed that the probabilistic neural network (PNN) had the minimum error rate and second types of errors, while the PNN model had the highest AUC value and was robust. To sum up, the algorithm makes some contributions to solve the financing problem of small and medium-sized enterprises in China. 相似文献
82.
为探讨粘附分子CD18、CD54和血小板CD62、CD63表达变化与急性脑梗塞(ACI)发病之间的关系,本文应用流式细胞仪(FCM)检测了52例ACI患者治疗前后CD18、CD54与CD62p、CD63两者的表达水平,并与30例正常人作对照。结果显示,脑梗塞组治疗前两者的表达水平均明显上调,与正常对照组比较均有显著差异... 相似文献
83.
肠促胰素对2型糖尿病胰岛功能的影响 总被引:1,自引:1,他引:0
胰岛β细胞功能障碍是2型糖尿病的重要发病机制之一,而现有治疗手段保护β细胞功能作用有限。最新的研究发现,肠促胰素不仅能够改善口细胞功能,而且能够避免低血糖、体重增加等不良反应,是治疗2型糖尿病的新途径。本文通过回顾公开发表的临床研究,对2型糖尿病口细胞功能、传统治疗及肠促胰素对β细胞功能的保护及延缓疾病进展作用进行了综... 相似文献
84.
克服肿瘤干细胞耐药性的策略和思路 总被引:1,自引:1,他引:0
肿瘤干细胞(cancersterncells,CSCs)是肿瘤细胞的祖细胞。已有的研究表明,肿瘤干细胞对多种化疗药物具有耐药性,是导致肿瘤治疗后复发的根源。研究针对肿瘤干细胞的治疗方法,克服肿瘤干细胞耐药性,将给肿瘤治疗模式带来全新的改变,有望彻底改善肿瘤患者的预后。 相似文献
85.
A number of people have suggested that there is a link between information integration and consciousness, and a number of algorithms for calculating information integration have been put forward. The most recent of these is Balduzzi and Tononi’s state-based Φ algorithm, which has factorial dependencies that severely limit the number of neurons that can be analyzed. To address this issue an alternative state-based measure known as liveliness has been developed, which uses the causal relationships between neurons to identify the areas of maximum information integration. This paper outlines the state-based Φ and liveliness algorithms and sets out a number of test networks that were used to compare their accuracy and performance. The results show that liveliness is a reasonable approximation to state-based Φ for some network topologies, and it has a much more scalable performance than state-based Φ. 相似文献
86.
《Quarterly journal of experimental psychology (2006)》2013,66(11):2081-2104
This paper relates human perception to the functioning of cells in the temporal cortex that are engaged in high-level pattern processing. We review historical developments concerning (a) the functional organization of cells processing faces and (b) the selectivity for faces in cell responses. We then focus on (c) the comparison of perception and cell responses to images of faces presented in sequences of unrelated images. Specifically the paper concerns the cell function and perception in circumstances where meaningful patterns occur momentarily in the context of a naturally or unnaturally changing visual environment. Experience of visual sequences allows anticipation, yet one sensory stimulus also “masks” perception and neural processing of subsequent stimuli. To understand this paradox we compared cell responses in monkey temporal cortex to body images presented individually, in pairs and in action sequences. Responses to one image suppressed responses to similar images for ~500 ms. This suppression led to responses peaking 100 ms earlier to image sequences than to isolated images (e.g., during head rotation, face-selective activity peaks before the face confronts the observer). Thus forward masking has unrecognized benefits for perception because it can transform neuronal activity to make it predictive during natural change. 相似文献
87.
Sikström S 《Cognitive Science》2006,30(2):243-275
An item that stands out (is isolated) from its context is better remembered than an item consistent with the context. This isolation effect cannot be accounted for by increased attention, because it occurs when the isolated item is presented as the first item, or by impoverished memory of nonisolated items, because the isolated item is better remembered than a control list consisting of equally different items. The isolation effect is seldom experimentally or theoretically related to the primacy or the recency effects—that is, the improved performance on the first few and last items, respectively, on the serial position curve. The primacy effect cannot easily be accounted for by rehearsal in short-term memory because it occurs when rehearsal is eliminated. This article suggests that the primacy, the recency, and the isolation effects can be accounted for by experience-dependent synaptic plasticity in neural cells. Neurological empirical data suggest that the threshold that determines whether cells will show long-term potentiation (LTP) or long-term depression (LTD) varies as a function of recent postsynaptic activity and that synaptic plasticity is bounded. By implementing an adaptive LTP-LTD threshold in an artificial neural network, the various aspects of the isolation, the primacy, and the recency effects are accounted for, whereas none of these phenomena are accounted for if the threshold is constant. This theory suggests a possible link between the cognitive and the neurological levels. 相似文献
88.
Strong C 《Theoretical medicine and bioethics》2006,27(5):433-453
The President’s Council on Bioethics has addressed the moral status of human preembryos in its reports on stem cell research and human therapeutic cloning. Although the Council has been criticized for being hand-picked to favor the right-to-life viewpoint concerning human preembryos, it has embraced the idea that the right-to-life position should be defended in secular terms. This is an important feature of the Council’s work, and it demonstrates a recognition of the need for genuine engagement between opposing sides in the debate over stem cell research. To promote this engagement, the Council has stated in secular terms several arguments for the personhood of human preembryos. This essay presents and critiques those arguments, and it concludes that they are unsuccessful. If the best arguments in support of the personhood of human preembryos have been presented by the Council, then there are no reasonable secular arguments in support of that view. 相似文献
89.
Fell J 《Consciousness and cognition》2004,13(4):709-729
This article sketches an idealized strategy for the identification of neural correlates of consciousness. The proposed strategy is based on a state space approach originating from the analysis of dynamical systems. The article then focuses on one constituent of consciousness, phenomenal awareness. Several rudimentary requirements for the identification of neural correlates of phenomenal awareness are suggested. These requirements are related to empirical data on selective attention, on completely intrinsic selection and on globally unconscious states. As an example, neuroscientific findings on synchronized gamma activity are categorized according to these requirements. 相似文献
90.
George RP 《Theoretical medicine and bioethics》2004,25(1):3-20
The author, a member of the U.S.President's Council on Bioethics, discussesethical issues raised by human cloning, whetherfor purposes of bringing babies to birth or forresearch purposes. He first argues that everycloned human embryo is a new, distinct, andenduring organism, belonging to the speciesHomo sapiens, and directing its owndevelopment toward maturity. He then distinguishesbetween two types of capacities belonging toindividual organisms belonging to this species,an immediately exerciseable capacity and abasic natural capacity that develops over time. He argues that it is the second type ofcapacity that is the ground for full moralrespect, and that this capacity (and itsconcomitant degree of respect) belongs tocloned human embryos no less than to adulthuman beings. He then considers and rejectscounter-arguments to his position, includingthe suggestion that the capacity of embryos isequivalent to the capacity of somatic cells,that full human rights are afforded only tohuman organisms with functioning brains, thatthe possibility of twinning diminishes themoral status of embryos, that the fact thatpeople do not typically mourn the loss of earlyembryos implies that they have a diminishedmoral status, that the fact that earlyspontaneous abortions occur frequentlydiminishes the moral status of embryos, andthat his arguments depend upon a concept ofensoulment. He concludes that if the moralstatus of cloned human embryos is equivalent tothat of adults, then public policy should bebased upon this assumption. 相似文献