瑶族神符概说

本文就瑶族神符的使用范畴、召请的神灵、绘制材料、源流及从盛行到逐渐淡化进行了概要论述,意在使读者对瑶族符咒文化有所了解,并能以平和心态,历史、客观地审视瑶族这一文化事像。

Shadow detection combining characters of human vision

A shadow detection method using pulse couple neural network inspired by the characters of human visual system is proposed.More precisely,lateral inhibition of human vision and coefficient of variation are combined together to improve the pulse couple neural network.Shadow detection is considered to be a shadow region segmentation problem.Experiment shows that the presented method is consistent with human vision compared to shadow detection methods based on HSV and pulse couple neural network(PCNN) by both subjective and objective assessments.

Efficient Selection of Linearly Independent Atomic Features for Accurate Machine Learning Potentials

Machine learning potentials are promising in atomistic simulations due to their comparable accuracy to first-principles theory but much lower computational cost.However,the reliability,speed,and transferability of atomistic machine learning potentials depend strongly on the way atomic configurations are represented.A wise choice of descriptors used as input for the machine learning program is the key for a successful machine learning representation.Here we develop a simple and efficient strategy to automatically select an optimal set of linearly-independent atomic features out of a large pool of candidates,based on the correlations that are intrinsic to the training data.Through applications to the construction of embedded atom neural network potentials for several benchmark molecules with less redundant linearly-independent embedded density descriptors,we demonstrate the efficiency and accuracy of this new strategy.The proposed algorithm can greatly simplify the initial selection of atomic features and vastly improve the performance of the atomistic machine learning potentials.

Offline Handwritten Characters Recognition Using Moments Features and Neural Networks

In this paper we revise the moment theory for pattern recognition designed, to extract patterns from the noisy character datas, and develop unconstrained handwritten. Amazigh character recognition method based upon orthogonal moments and neural networks classifier. We argue that, given the natural flexibility of neural network models and the extent of parallel processing that they allow, our algorithm is a step forward in character recognition. More importantly, following the approach proposed, we apply our system to two different databases, to examine the ability to recognize patterns under noise. We discover overwhelming support for different style of writing. Moreover, this basic conclusion appears to remain valid across different levels of smoothing and insensitive to the nuances of character patterns. Experiments tested the effect of set size on recognition accuracy which can reach 97.46%. The novelty of the proposed method is independence of size, slant, orientation, and translation. The performance of the proposed method is experimentally evaluated and the promising results and findings are presented. Our method is compared to K-NN （k-nearest neighbors） classifier algorithm; results show performances of our method.

陇中地区丧葬“抱砖”习俗发微——兼谈墓券文中“直符”神的演变

"抱砖"是流行于陇中(甘肃中部)地区的一种丧葬习俗,即新坟立祖时墓券砖的安放仪式。陇中地区的"抱砖"习俗体现了民俗文化因时、因事、因地而变的特征,在下葬环节举行"抱砖"仪式是其独特表现。张传玺先生归纳形成了墓券券文广例,并认为券文中的"直符"即"甲寅日别状"等"轮值主符神仙"。事实上,墓券中的"直符"神应为道教中的"随斗十二神",发挥着奉命保护墓主、镇邪伏魔的功效,而张传玺先生所列举的"甲寅日别状"等实为"时序鬼"。墓券文中"直符"神的书写,经历了由起初对"随斗十二神"的全部列举到后来从中确定四位神祇为岁直符、月直符、日直符、时直符的演变过程。

TGFβ signaling hyperactivation-induced tumorigenicity during the derivation of neural progenitors from mouse ESCs

Clinical therapies of pluripotent stem cells （PSCs）-based transplantation have been hindered by frequent development of terato- mas or tumors in animal models and clinical patients. Therefore, clarifying the mechanism of carcinogenesis in stem cell therapy is of great importance for reducing the risk of tumorigenicity. Here we differentiate Oct4-GFP mouse embryonic stem cells （mESCs） into neural progenitor cells （NPCs） and find that a minority of Oct4＋ cells are continuously sustained at Oct4＋ state. These cells can be enriched and proliferated in a standard ESC medium. Interestingly, the differentiation potential of these enriched cells is tightly restricted with much higher tumorigenic activity, which are thus defined as differentiation-resistant ESCs （DR-ESCs）. Transcriptomic and epigenomic analyses show that DR-ESCs are characterized by primordial germ cell-like gene sig- natures （Dazl, Rec8, Stro8, BUmp1, etc.） and specific epigenetic patterns distinct from mESCs. Moreover, the DR-ESCs possess germ cell potential to generate Sycp3＋ haploid cells and are able to reside in sperm-free spermaduct induced by busulfan. Finally, we find that TGFβ signaling is overactivated in DR-ESCs, and inhibition of TGFβ signaling eliminates the tumorigenicity of mESC-derived NPCs by inducing the full differentiation of DR-ESCs. These data demonstrate that these TGFβ-hyperactivated germ ceU-like DR-ESCs are the main contributor for the tumorigenicity of ESCs-derived target cell therapy and that inhibition of TGFβ signaling in ESC-derived NPC transplantation could drastically reduce the risk of tumor development. Keywords： embryonic stem cells, differentiation-resistant ESCs, tumorigenicity, germ cell, TGFβ signaling