27,624 research outputs found
Xi jun jun luo zhong de ji qun yun dong
No full textPh.D.Numerous investigations during the past decade have been focused on the collective motion in microbial systems and generated tremendous advances. Nevertheless, collective motion in structured microbial communities is far less understood compared to that in homogeneous microbial systems. We sought to investigate the collective behaviors of motile cells in bacterial colonies which represent perhaps the simplest form of structured microbial communities. Here, we have studied several types of bacterial collective motion observed in flagellated bacterial colonies, including the self-organization of motile rings and colony-scale unidirectional vortices. We suggest that both steric and hydrodynamic interactions contribute to the emergence of these remarkable collective motion in bacterial colonies. Our findings present unique forms of bacterial self-organization that may influence population structure and material distribution in bacterial communities. Moreover, our work may provide us a better understanding of active matter behaviors in complex fluids or gels.在過去的幾十年中，許多工作致力於研究微生物的集體運動，並取得了巨大進展。然而，結構化群落環境中的微生物集體運動還遠沒有被了解。我們試圖研究運動的細菌菌落中的集體行為，細菌菌落可能代表了最簡單的結構化微生物群落。在這篇論文中，我們研究了在細菌菌落中觀察到的幾種細菌集體運動模式，包括自組織在菌落邊緣形成運動環和菌落尺度的渦旋。我們認為，空間和流體相互作用都有助於細菌菌落中這些有趣的集體運動的出現。我們的發現提出了細菌自組織的獨特形式，可能會影響細菌群落中的種群結構和物質分佈。此外，我們的工作可能使我們對複雜流體或凝膠中活性物質的行為有更好的了解。Xu, Haoran = 細菌菌落中的集群運動 / 徐浩然.Thesis Ph.D. Chinese University of Hong Kong 2020.Includes bibliographical references (leaves 71-82).Abstracts also in Chinese.Title from PDF title page (viewed on March 28, 2022).Xu, Haoran = Xi jun jun luo zhong de ji qun yun dong / Xu Haoran
Direct numerical simulation of inert droplet effects on scaler dissipation rate in turbulant and non-reacting shear layers
No full textThree-dimensional direct numerical simulation has been performed to investigate the effects of inert evaporating droplets on scalar dissipation rate ? in temporally-developing turbulent reacting and non-reacting mixing layers with the Reynolds number based on the vorticity thickness up to 8000 and the number of traced Lagrangian droplets up to 107. The detailed instantaneous field analysis and ensemble-averaged statistics reveal complex interactions among combustion, droplet dynamics and evaporation, all of which have a considerable influence on ?. The presence of inert evaporating droplets promotes ? in both non-reacting and reacting mixing layers. In the latter, combustion reduces ?, so when combustion is suppressed by evaporating droplets, ? is enhanced. The transport equation of ? has been analyzed to investigate the various effects on ? in detail. The terms in the equation contain explicitly the evaporation rate and its spatial derivative, acting as a sink and a source for ?, respectively. On the whole, the net effect of the evaporation-rate terms is to promote ?. However, the production and dissipation terms are the dominant source and sink terms, respectively
Comparison of tests for spatial heterogeneity on data with global clustering patterns and outliers
No full textAbstract Background The ability to evaluate geographic heterogeneity of cancer incidence and mortality is important in cancer surveillance. Many statistical methods for evaluating global clustering and local cluster patterns are developed and have been examined by many simulation studies. However, the performance of these methods on two extreme cases (global clustering evaluation and local anomaly (outlier) detection) has not been thoroughly investigated. Methods We compare methods for global clustering evaluation including Tango's Index, Moran's I, and Oden's I*pop; and cluster detection methods such as local Moran's I and SaTScan elliptic version on simulated count data that mimic global clustering patterns and outliers for cancer cases in the continental United States. We examine the power and precision of the selected methods in the purely spatial analysis. We illustrate Tango's MEET and SaTScan elliptic version on a 1987-2004 HIV and a 1950-1969 lung cancer mortality data in the United States. Results For simulated data with outlier patterns, Tango's MEET, Moran's I and I*pop had powers less than 0.2, and SaTScan had powers around 0.97. For simulated data with global clustering patterns, Tango's MEET and I*pop (with 50% of total population as the maximum search window) had powers close to 1. SaTScan had powers around 0.7-0.8 and Moran's I has powers around 0.2-0.3. In the real data example, Tango's MEET indicated the existence of global clustering patterns in both the HIV and lung cancer mortality data. SaTScan found a large cluster for HIV mortality rates, which is consistent with the finding from Tango's MEET. SaTScan also found clusters and outliers in the lung cancer mortality data. Conclusion SaTScan elliptic version is more efficient for outlier detection compared with the other methods evaluated in this article. Tango's MEET and Oden's I*pop perform best in global clustering scenarios among the selected methods. The use of SaTScan for data with global clustering patterns should be used with caution since SatScan may reveal an incorrect spatial pattern even though it has enough power to reject a null hypothesis of homogeneous relative risk. Tango's method should be used for global clustering evaluation instead of SaTScan.</p
GSA and BIGD: Filling the Gap of Bioinformatics Resource and Service in China*
No full textIn the 2017 first issue of this Journal - Genomes, Proteomes and Bioinformatics - a special database article entitled ‘‘GSA: Genome Sequence Archive” is published. This article provides a brief introduction to the platform developed by the authors from the BIG Data Center (BIGD) of Beijing Institute of Genomics (BIG), Chinese Academy of Sciences (CAS). The aim of the GSA project is to collect, integrate, and archive raw sequence data submitted by domestic and international users. It is one of the major activities being carried on by a team of around 50 young bioinformaticians at BIGD. In addition to the GSA system, they are also working on several bioinformatics service-orientated projects as described in one of their recent publications.The author thanks Dr. Jun Yu for his critical commentsSCI(E)中国科学引文数据库(CSCD)EDITORIAL MATERIAL111-131
Two new synonyms of Rhopalopsole basinigra Yang & Yang, 1995 (Plecoptera: Leuctridae) with taxonomic notes on Rhopalopsole tianmuana Sivec & Harper, 2008
No full textLuo, Jun, Yao, Gang, Wang, Mingju, Li, Weihai (2022): Two new synonyms of Rhopalopsole basinigra Yang & Yang, 1995 (Plecoptera: Leuctridae) with taxonomic notes on Rhopalopsole tianmuana Sivec & Harper, 2008. Zootaxa 5188 (3): 290-296, DOI: 10.11646/zootaxa.5188.3.
Chinese culture through video: lines of analysis and research perspectives
No full textThis paper proposes a perspective analysis of perceptions and representations of Chinese Culture by young people with multinational backgrounds, they used the practice of video communication within a research context to promote effective practices of cross-cultural communication and the Chinese Culture, as an interpersonal cultural experience. The aim is to underline how young people of different countries perceive, understand and rebuild the Chinese Culture using videos, for example which are the most used representations cultural and values factors, and what is the level of effectiveness of the communication techniques used. Up until today, we have examined 100 of the videos made by the young producers involved in the "Looking China" project. The research approach can be included in the mixed methods (Tashakkori and Teddlie 2010). The videos were analysed individually through a grid of analyses, which focuses on the content, both on the qualitative indicators of the Chinese Culture and on the techniques used for the video communication. The results were shown and compared, using quantitative procedures that can point out to the main similarities and differences among the indicators measured. By comparison, the results show that there are interesting lines of interpersonal analysis on the experience of the Chinese Culture and of elements that could, in practical and theoretical terms, improve the practices of cross-cultural communication and help us to create spaces of knowledge on the sharing of "the other" and of the Chinese Culture through the video
Proline-rich tyrosine kinase 2 mediates gonadotropin-releasing hormone signaling to a specific extracellularly regulated kinase-sensitive transcriptional locus in the luteinizing hormone beta-subunit gene
No full textG protein-coupled receptor regulation of gene transcription primarily occurs through the phosphorylation of transcription factors by MAPKs. This requires transduction of an activating signal via scaffold proteins that can ultimately determine the outcome by binding signaling kinases and adapter proteins with effects on the target transcription factor and locus of activation. By investigating these mechanisms, we have elucidated how pituitary gonadotrope cells decode an input GnRH signal into coherent transcriptional output from the LH beta-subunit gene promoter. We show that GnRH activates c-Src and multiple members of the MAPK family, c-Jun NH2-terminal kinase 1/2, p38MAPK, and ERK1/2. Using dominant-negative point mutations and chemical inhibitors, we identified that calcium-dependent proline-rich tyrosine kinase 2 specifically acts as a scaffold for a focal adhesion/cytoskeleton-dependent complex comprised of c-Src, Grb2, and mSos that translocates an ERK-activating signal to the nucleus. The locus of action of ERK was specifically mapped to early growth response-1 (Egr-1) DNA binding sites within the LH beta-subunit gene proximal promoter, which was also activated by p38MAPK, but not c-Jun NH2-terminal kinase 1/2. Egr-1 was confirmed as the transcription factor target of ERK and p38MAPK by blockade of protein expression, transcriptional activity, and DNA binding. We have identified a novel GnRH-activated proline-rich tyrosine kinase 2-dependent ERK-mediated signal transduction pathway that specifically regulates Egr-1 activation of the LH beta-subunit proximal gene promoter, and thus provide insight into the molecular mechanisms required for differential regulation of gonadotropin gene expression
Guangdong ji Xianggang dui tou bao jun su zhong du min gan lin qiu jun gan ran de fen zi liu xing bing xue ji wei xian yin su yan jiu
No full textLuo, Tongyong.Thesis Ph.D. Chinese University of Hong Kong 2016.Includes bibliographical references (leaves 181-209).Abstracts also in Chinese; appendix 1 in Chinese.Title from PDF title page (viewed on 16, November, 2016).Luo, Tongyong
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