83 research outputs found
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Reimagining Chairman Mao : the emerging Mao fandom and its multimodal persona construction on Chinese social media
No full textThis study investigates the resurgence of Mao Zedong admiration among Chinese youth on the video-sharing platform Bilibili, conceptualizing it as a form of political fandom. Drawing on cultural studies and political communication, it examines how fandom-produced videos construct Mao’s political persona through multimodal strategies and reflect the shared beliefs and ideologies of fan communities. Using multimodal critical discourse analysis (MCDA), 47 of the most popular Mao-related fandom videos were coded and analyzed across visual, verbal, and auditory modes. The analysis identified six recurring personas: a people-oriented leader, a caring elder, a brilliant strategist, a tragic hero, an anti-capitalist fighter, and a globally influential figure. These portrayals, while influenced by state-promoted narratives of Mao, also develop distinctive characteristics, revealing the agency of ordinary citizens in reinterpreting historical leaders. By situating these practices within China’s political and cultural context, the study contributes to scholarship on political fandom in authoritarian regimes and offers insights into the political culture of contemporary Chinese youth.Journalism and Medi
On the criteria of jet types during a bubble collapse near the tissue-mimicking boundary
No full textThe collapse of a cavitation bubble near a tissue membrane generates intense microscopic flows, emits shock wave, and can lead to membrane damage. Experimental works show that the collapse of a cavitation bubble leads to more violent two axial jets flow with decreasing bubble-boundary distance. The critical stand-off distance for the formation of such a jet flow varies largely under different material properties. We investigate the evolution of cavitation induced jet flow experimentally and theoretically comprehensively. A dimensionless impulse is proposed based on image-source model, considering the influence of boundary. A regime map is constructed, revealing a unique law for various materials. The current work may offer insight into the application of cavitation bubbles in biomedical engineering. (c) 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC) license (https://creativecommons.org/licenses/by-nc/4.0/)
Visual Interpretation of Recurrent Neural Network on Multi-dimensional Time-series Forecast
No full textRecent attempts at utilizing visual analytics to interpret Recurrent Neural Networks (RNNs) mainly focus on natural language processing (NLP) tasks that take symbolic sequences as input. However, many real-world problems like environment pollution forecasting apply RNNs on sequences of multi-dimensional data where each dimension represents an individual feature with semantic meaning such as PM2.5 and SO2. RNN interpretation on multi-dimensional sequences is challenging as users need to analyze what features are important at different time steps to better understand model behavior and gain trust in prediction. This requires effective and scalable visualization methods to reveal the complex many-to-many relations between hidden units and features. In this work, we propose a visual analytics system to interpret RNNs on multi-dimensional time-series forecasts. Specifically, to provide an overview to reveal the model mechanism, we propose a technique to estimate the hidden unit response by measuring how different feature selections affect the hidden unit output distribution. We then cluster the hidden units and features based on the response embedding vectors. Finally, we propose a visual analytics system which allows users to visually explore the model behavior from the global and individual levels. We demonstrate the effectiveness of our approach with case studies using air pollutant forecast applications.Accepted author manuscriptComputer Graphics and Visualisatio
Energy Fuels
No full textA hybrid power system based on coal pyrolysis and steam integration is proposed to improve the performance of power plants. The most outstanding features of the system are a pyrolysis process integrated with a circulating fluidized bed boiler and power generation by the steam integration. The model of the hybrid power system is set up by THERMOFLEX software and Aspen Plus. Results show that the thermal efficiency of pyrolysis process can achieve values of 90%95%, and the majority of the energy used by the pyrolysis is consumed during the drying and quench processes. Compared with a conventional steam cycle power system, the gross electric efficiency and thermal efficiency of the new system are increased by 1.9% and 5.1%, respectively. Energy and exergy analyses are presented to study the performance differences of two systems. Exergy destruction of the boiler with steam integration is decreased in the new system. Exergy destruction of gas turbines is lower than that of the boiler. Although additional exergy loss occurs in the pyrolyzer and heat recovery steam generator, the overall exergy loss of the new system is less than that of the conventional system.A hybrid power system based on coal pyrolysis and steam integration is proposed to improve the performance of power plants. The most outstanding features of the system are a pyrolysis process integrated with a circulating fluidized bed boiler and power generation by the steam integration. The model of the hybrid power system is set up by THERMOFLEX software and Aspen Plus. Results show that the thermal efficiency of pyrolysis process can achieve values of 90%95%, and the majority of the energy used by the pyrolysis is consumed during the drying and quench processes. Compared with a conventional steam cycle power system, the gross electric efficiency and thermal efficiency of the new system are increased by 1.9% and 5.1%, respectively. Energy and exergy analyses are presented to study the performance differences of two systems. Exergy destruction of the boiler with steam integration is decreased in the new system. Exergy destruction of gas turbines is lower than that of the boiler. Although additional exergy loss occurs in the pyrolyzer and heat recovery steam generator, the overall exergy loss of the new system is less than that of the conventional system
Comparison of Carbon-Use Efficiency Among Different Land-Use Patterns of the Temperate Steppe in the Northern China Pastoral Farming Ecotone
No full textCarbon-use efficiency (CUE) is the proportion of gross primary production converted to net primary production. Changes to CUE strongly influence ecosystem carbon budgets and turnover. Little is known about the response of ecosystem CUE to human-induced land-use change, which limits the accurate evaluation of the environmental influence of large-scale steppe-use changes in northern China. We investigated the components of ecosystem carbon exchange and CUE under three typical steppe-use patterns in Xilinhot, Inner Mongolia. The results showed that CUE in grazing and grazing-excluded steppe were not significantly different (both over 0.7) but were significantly higher than in cultivated steppe (0.57). Ecosystem respiration and its components, including autotrophic respiration (Ra), aboveground respiration, heterotrophic respiration and belowground respiration showed significant negative correlation with CUE. Ra is the most important factor explaining the variation of CUE between different steppe-use patterns (p < 0.001, 97%); Ra change may be the primary factor driving CUE variation between steppe-use patterns. Leaf area index of different grassland-use patterns also showed a significant negative correlation with CUE (p < 0.001, 91%). These findings may help to improve accurate prediction of the environmental and climatic consequences of large-scale land-use change
Grazing Exclusion, a Choice between Biomass Growth and Species Diversity Maintenance in Beijing—Tianjin Sand Source Control Project
No full textGrasslands in northern China form an important ecological barrier that prevents and controls desertification. The Beijing–Tianjin Sand Source Control (BTSSC) Project has been implemented to restore grassland in order to control sand sourced pollution. This study aimed to understand the impacts of four applied restoration practices on the productivity, composition, and species diversity of vegetation communities in the BTSSC Project. The results indicated the following: (1) All the restoration practices tended to increase the height and cover of communities, and the effect was most obvious where grazing was excluded; (2) total biomass (87%), above-ground biomass (164%) and below-ground biomass (58%) only increased consistently when grazing was excluded from the steppe; (3) fenced and grazing exclusion practice significantly increased the abundance of species in communities, but all the practices tended to decrease the evenness of species; and, (4) the correlation analysis revealed that the Shannon–Wiener diversity index, and Pielou evenness index, showed significant negative correlations with the above-ground biomass of grassland communities after restoration, while no significant relationships were shown in reference plots. Our comparison of applied practices in the BTSSC project revealed that grazing exclusion might be a high priority for more successful restoration in this region
Ju jie chang zheng xiao shu mo xing de you dao xing duo neng gan xi bao ding xiang you dao fen hua wei shen jing ji gan xi bao de yan jiu
No full textPh.D.Neural crest cells (NCCs) are a group of embryonic cells which migrate long distances from the neural tube (i.e. developing central nervous system) to different locations of the embryo to form a multitude of derivatives. Based on their migration ability and multipotency, NCCs can be a potential cell source for cell therapy for birth defects involving abnormal NCC development such as Waardenburg syndrome and Hirschsprung’s disease (HSCR). However, the limited availability of NCCs directly from embryos or primary cultures is one of the main difficulties in developing this cell type into a useful cell source for cell therapy. With the discovery of induced pluripotent stem cells (iPSCs) which possess an unlimited ability of self-renewal, studies have already begun to focus on the in vitro induction of NCCs from iPSCs. Moreover, in order to investigate the feasibility of using patient iPSC-derived NCCs for cell-based therapy, the Dominant megacolon (Dom) mouse model of HSCR was employed in the present study. The present study consists of the following two parts with the aim of exploring the potential of iPSCs in cell therapy for HSCR.In the first part of the study, a three-step induction programme was established for inducing normal mouse iPSCs into NCCs. The first step involved reprogramming of mouse embryonic fibroblasts from wild type (WT) Dom mice into iPSCs by transfection with the four Yamanaka transcription factors with the subsequent formation of clusters of iPSCs known as neuroepithelial spheres in the sphere formation medium containing B27, N2 and FGF2. An addition of BMP4 to the medium enhanced the gene expression levels of NCC markers Sox10, Ap-2α, Slug and Snail, and also induced more than 40% of the iPSCs to become p75 immunoreactive 6 days after induction. The next step induced emigration of NCCs from the neuroepithelial spheres on a laminin-coated culture surface in the NCC induction medium containing FGF2 and EGF. Expression of NCC markers Sox10, Ap-2α, Slug, Snail, id2, id3 and nestin was upregulated when cells emigrated from neuroepithelial spheres. The last step aimed to expand and maintain NCCs in an undifferentiated stage in the NCC maintenance medium containing GDNF. Real-time PCR and immunostaining results showed that 50 ng/ml GDNF in the medium could keep NCCs remained undifferentiated with the continuous expression of NCC markers Sox10, Ap- 2α, nestin and FoxD3. Moreover, by adding 0.5 μM retinoic acid at the sphere formation stage, the gene expression pattern of induced NCCs became more similar to that of vagal NCCs. Induced NCCs were able to differentiate into glial cells, neurons, smooth muscle cells, chondrocytes and osteocytes in vitro under different differentiation conditions. When transplanted to E13.5 hindgut explants ex vivo, induced NCCs migrated and gave rise to TuJ1 immunoreactive neurons 3 days after transplantation.In the second part of the study, skin fibroblasts of Dom mutant mice were also reprogrammed to iPSCs. However, the colony formation ability was lower in Dom iPSCs than WT iPSCs. Dom iPSCs also showed defective pluripotency although their cell proliferation rate was similar to that of WT iPSCs. Moreover, the ability of Dom iPSCs to form NCCs using the same three-step NCCs induction programme established previously was found to be lower. To further characterize the differences between the WT iNCCs and Dom iNCCs, the in vitro and ex vivo migration and differentiation abilities were determined. Dom iNCCs exhibited lower migration and invasion abilities in the scratch and trans-well assays in vitro. When iPSCs were transplanted to the hindgut explant cultured ex vivo, Dom iPSCs were not able to differentiate into TuJ1 immunoreactive neurons 3 days post-transplantation, and they were also less able to migrate long distances in the hindgut explant as compared to WT iPSCs.Hence, our results indicated that both WT and Dom iPSCs could be induced to form NCCs in vitro without any gene modifications, and the induced NCCs derived from Dom iPSCs were found to be less able to migrate long distances and differentiate into neurons in the embryonic gut ex vivo as compared with WT iNCCs. iNCCs would be useful in the NCC research and cell-based transplantation studies.作為胚胎發育過程中的關鍵細胞，神經嵴細胞可以從神經管遠距離遷移到胚胎的不同部位並分化成多種細胞類型（⽐如中樞神經系統中的神經細胞）。由於神經嵴細胞具有較強的遷移特性和多能性，其可以被⽤於治療由於神經嵴細胞異常發育分化⽽引起的疾病，⽐如⽡登伯⾰⽒症候群以及巨結腸症。儘管如此，由於從胚胎或者從成體中提取神經嵴細胞較為困難並且原代神經嵴細胞較難培養，將這些細胞⽤於相關疾病的細胞治療的可能性被⼤⼤降低。不過，誘導性多能幹細胞的發現為解決上述問題帶來了新的希望，由於誘導性多能幹細胞能夠無限增殖，很多研究開始致⼒於在體外將誘導性多能幹細胞分化為神經嵴細胞。為了探索對巨結腸症病⼈採取幹細胞治療的可⾏性，本研究以⼀種巨結腸症Dominant megacolon（Dom）⼩⿏模型作為研究對象。本研究主要通過兩部分內容來證明利⽤多潛能幹細胞治療巨結腸症的可能性。在第⼀部份內容中，我們發明了⼀種通過三個步驟逐漸將多潛能幹細胞在體外分化為神經嵴細胞的⽅法。該⽅法以巨結腸症⼩⿏模型的野⽣型為研究對象，⾸先將該野⽣型⼩⿏的胚胎成纖維細胞通過重表達四種Yamanaka 因⼦重編程為多潛能幹細胞。神經嵴細胞體外誘導的第⼀步是將多潛能幹細胞通過包含B27，N2 以及纖維細胞⽣⾧因⼦2（FGF2）等⽣⾧因⼦的培養液轉化為神經上⽪幹細胞球。本研究發現⾻型態發⽣蛋⽩以及維⽣素A 可以明顯提⾼神經嵴細胞標記物基因Sox10, Ap-2a, Slug 以及Snail 的表達⽔平, 並且經過6 天誘導，近50%的多潛能幹細胞轉變為p75 陽性細胞。第⼆步則是將包含神經嵴細胞的神經上⽪幹細胞球種在含有層黏連蛋⽩塗層的培養⽫中，培養液更換為含有FGF2 以及上⽪⽣⾧因⼦（EGF）的神經嵴細胞誘導培養液（NCIM）以便於神經嵴細胞從神經上⽪幹細胞球中遷出。本研究發現遷出的細胞中神經嵴細胞標記基因Sox10, Ap-2a, Slug，Snail, id2 以及id3 的表達⽔平明顯升⾼。該誘導⽅法的最後⼀步則是將遷出的神經嵴細胞培養與含有神經膠質細胞滋養因⼦（GDNF）的培養液中以便擴增並維持其幹細胞特性。實時定量聚合酶鏈式反應以及免疫螢光染⾊結果顯⽰50 ng/ml 的GDNF 可以維持⼤部分神經嵴細胞不會進⼀步分化，並且持續表達神經嵴細胞標記基因Sox10, Ap-2a, nestin 以及FoxD3。並且在神經上⽪幹細胞球的形成過程中添加0.5 M 維⽣素A 可以促使所誘導的神經嵴細胞的基因表達模式更接近於原代培養的迷⾛神經嵴細胞。同時，所誘導的神經嵴細胞通過不同的分化條件可以在體外被分化為神經膠質細胞，神經元，平滑肌細胞，軟⾻細胞以及成⾻細胞。本研究發現將所誘導的神經嵴細胞移植於體外培養的⼩⿏E13.5 後腸3 天後，這些細胞可以短距離遷移並且分化為TuJ1 陽性神經元細胞。在本研究的第⼆部分內容中，來源於巨結腸症模型Dom ⼩⿏的胚胎成纖維細胞⾸先被重編程為誘導性多能幹細胞。不過相⽐於野⽣型⼩⿏，Dom ⼩⿏的誘導性多能幹細胞的克隆形態形成能⼒存在⼀定的缺陷，同时其全能性更難維持。不過在細胞增殖⽔平⽅⾯，Dom ⼩⿏和野⽣型⼩⿏的誘導性多能幹細胞沒有明顯差別。通過同樣的⽅法誘導所得的Dom ⼩⿏神經嵴細胞的⽐例也較野⽣型⼩⿏的低。隨後，本研究也⽐較了Dom ⼩⿏誘導性神經嵴細胞與野⽣型⼩⿏誘導性神經嵴細胞在細胞遷移與分化能⼒之間的差別。體外研究顯⽰，Dom ⼩⿏誘導性神經嵴細胞細胞遷移和侵襲能⼒都弱於野⽣型⼩⿏誘導性神經嵴細胞。雖然將兩種細胞移植於體外培養的⼩⿏E13.5 後腸3 天後，Dom ⼩⿏誘導性神經嵴細胞細胞遷移距離明顯低於野⽣型⼩⿏的誘導性神經嵴細胞細胞，并且仅在野⽣型⼩⿏誘導性神經嵴細胞中發現TuJ1 陽性神經元的形成。因此，我們的研究結果顯⽰野⽣型和Dom ⼩⿏的誘導性多能幹細胞均可以在體外被誘導分化為神經嵴細胞，並且體外移植实验结果顯⽰，通過該⽅法分化所得的神經嵴細胞在胚胎尾腸中可以遷徙並分化為神經元。通過本⽅法所誘導的神經嵴細胞可以⽤於有關神經嵴細胞發育以及細胞移植相關的研究。Niu, Yuzhe.Thesis Ph.D. Chinese University of Hong Kong 2017.Includes bibliographical references (leaves 177-200).Abstracts also in Chinese.Title from PDF title page (viewed on …).Niu, Yuzhe
Foliar carbon, nitrogen, and phosphorus stoichiometry in a grassland ecosystem along the Chinese Grassland Transect
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Quadratic ideals and Rogers–Ramanujan recursions
Get PDFWe give an explicit recursive description of the Hilbert series and Gröbner bases for the family of quadratic ideals defining the jet schemes of a double point. We relate these recursions to the Rogers–Ramanujan identity and prove a conjecture of the second author, Oblomkov and Rasmussen
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