1,045 research outputs found

    Matrix Formulation of Hamiltonian Structures of Constrained KP Hierarchy

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    We give a matrix formulation of the Hamiltonian structures of constrained KP hierarchy. First, we derive from the matrix formulation the Hamiltonian structure of the one-constraint KP hierarchy, which was originally obtained by Oevel and Strampp. We then generalize the derivation to the multi-constraint case and show that the resulting bracket is actually the second Gelfand-Dickey bracket associated with the corresponding Lax operator. The matrix formulation of the Hamiltonian structure of the one-constraint KP hierarchy in the form introduced in the study of matrix model is also discussedComment: 19 pages, Revtex, no figures. Minor changes, reference correcte

    Rough-set-based ADR signaling from spontaneous reporting data with missing values

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    AbstractSpontaneous reporting systems of adverse drug events have been widely established in many countries to collect as could as possible all adverse drug events to facilitate the detection of suspected ADR signals via some statistical or data mining methods. Unfortunately, due to privacy concern or other reasons, the reporters sometimes may omit consciously some attributes, causing many missing values existing in the reporting database. Most of research work on ADR detection or methods applied in practice simply adopted listwise deletion to eliminate all data with missing values. Very little work has noticed the possibility and examined the effect of including the missing data in the process of ADR detection.This paper represents our endeavor towards the exploration of this question. We aim at inspecting the feasibility of applying rough set theory to the ADR detection problem. Based on the concept of utilizing characteristic set based approximation to measure the strength of ADR signals, we propose twelve different rough set based measuring methods and show only six of them are feasible for the purpose. Experimental results conducted on the FARES database show that our rough-set-based approach exhibits similar capability in timeline warning of suspicious ADR signals as traditional method with missing deletion, and sometimes can yield noteworthy measures earlier than the traditional method

    PlantPAN: Plant promoter analysis navigator, for identifying combinatorial cis-regulatory elements with distance constraint in plant gene groups

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    <p>Abstract</p> <p>Background</p> <p>The elucidation of transcriptional regulation in plant genes is important area of research for plant scientists, following the mapping of various plant genomes, such as <it>A. thaliana</it>, <it>O. sativa </it>and <it>Z. mays</it>. A variety of bioinformatic servers or databases of plant promoters have been established, although most have been focused only on annotating transcription factor binding sites in a single gene and have neglected some important regulatory elements (tandem repeats and CpG/CpNpG islands) in promoter regions. Additionally, the combinatorial interaction of transcription factors (TFs) is important in regulating the gene group that is associated with the same expression pattern. Therefore, a tool for detecting the co-regulation of transcription factors in a group of gene promoters is required.</p> <p>Results</p> <p>This study develops a database-assisted system, PlantPAN (Plant Promoter Analysis Navigator), for recognizing combinatorial <it>cis</it>-regulatory elements with a distance constraint in sets of plant genes. The system collects the plant transcription factor binding profiles from PLACE, TRANSFAC (public release 7.0), AGRIS, and JASPER databases and allows users to input a group of gene IDs or promoter sequences, enabling the co-occurrence of combinatorial transcription factor binding sites (TFBSs) within a defined distance (20 bp to 200 bp) to be identified. Furthermore, the new resource enables other regulatory features in a plant promoter, such as CpG/CpNpG islands and tandem repeats, to be displayed. The regulatory elements in the conserved regions of the promoters across homologous genes are detected and presented.</p> <p>Conclusion</p> <p>In addition to providing a user-friendly input/output interface, PlantPAN has numerous advantages in the analysis of a plant promoter. Several case studies have established the effectiveness of PlantPAN. This novel analytical resource is now freely available at <url>http://PlantPAN.mbc.nctu.edu.tw</url>.</p

    Radiosurgery for Vestibular Schwannomas

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    BackgroundRadiosurgery has been established as an important alternative to microsurgery. We report our experience with radiosurgery for tumor control and the complications of unilateral vestibular schwannomas.MethodsWe reviewed our early experience regarding clinical presentation, management and outcomes in 45 patients with acoustic schwannomas who underwent gamma knife stereotactic radiosurgery. The median follow-up period was 25 months (range, 6-48 months). Thirteen patients had undergone 1 or more previous resections before radiosurgery; 32 underwent radiosurgery as the first procedure. Median tumor volume was 4.5 mL (range, 0.5-30.0), and median radiotherapy dose was 11.5 Gy (range, 10.5-14.0 Gy).ResultsTumor control was achieved in 43 patients (95.6%). Loss of central contrast enhancement was a characteristic change and was noted in 29 patients (64.4%). Reduction in tumor size was shown in 15 patients (33.3%). Thirteen patients (28.9%) had good or serviceable hearing preoperatively, and in all of these, the preoperative status was retained immediately after radiosurgery. At follow-up, however, 10 patients (76.9%) had preserved hearing and 3 (23.1%) had reduced hearing on the treated side. Hearing in 1 patient that was not serviceable preoperatively later improved to a serviceable level. No patients had delayed facial palsy or lower cranial nerve dysfunction, but one had delayed trigeminal sensory loss.ConclusionRadiosurgery achieved a high tumor control rate and a relatively low post-radiosurgical complication rate for acoustic neuromas

    Xi Jin-Ping's world cup dreams: from a major sports country to a world sports power

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    Football is among the world’s most popular sports. It is also one which China has sought to develop in the field of global professional sport. Nevertheless, the professionalization of football in China has not to date actually improved China's Olympic achievement in the sport. In stark contrast to the glory of being the country that won most gold medals at the 2008 Olympics, China’s poor football performance has been troublesome for the country’s leader. In 2009, newly elected Xi Jin-Ping made a public statement about promoting elite football and expressed his personal hope that China would be capable of both qualifying for the final stages and winning the FIFA World Cup. With such concern on the part of the state leader, attention turned to football, with many private enterprises beginning to echo government policy by demonstrating a willingness to promote elite football. In addition, to accelerate football development, the Chinese government promised to take action on the separation of government and football associations. Research on this process was based on the theoretical framework of state corporatism derived from the work of Schmitter (1974). Semi-structured interviews were conducted as the method of data collection aimed at helping us understand how Chinese government either integrated or controlled relevant stakeholders such as NGOs and private enterprises, and further, to discuss the interactions between them

    Aspectos sobre a decisão de canais no pequeno varejo: a escolha entre o atacado e o atacarejo

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    This article talks about purchase decision from small and medium retailers from Piracicaba Region, São Paulo State. The bibliographic and field research showed the main influence factors and decision criteria of small retailers for purchase, related to the choice between the traditional wholesale and the wholesale and retail outlet, which is a type of store that allows the wholesaler sales to sell to small or medium-sized retailers and for end consumers who are looking for the best price. The topics treated are the distribution channels, types of agents, the role of each one and the retailers' decision of purchasing. The exploratory research was applied to small and medium-sized retailers from Piracicaba Region, Sao Paulo State Countryside. From the eight case studies it was possible to identify the aspects considered relevant for retailers in the purchase decision and partner choice. Retailers were expressed by five attributes considered the most relevant, they are: convenience, variety, price, reliability and quantity.Este artigo aborda a temática da decisão de compra dos varejistas de pequeno e de médio porte da região de Piracicaba, SP. O levantamento bibliográfico, bem como a pesquisa de campo, apontaram os principais fatores de influência e os critérios de decisão de compra de pequenos varejistas quanto à escolha entre o atacado tradicional e o atacarejo, que é um tipo de loja que permite ao atacadista vender aos varejistas de pequeno ou de médio porte e aos consumidores finais que estão à procura do melhor preço. Os tópicos abordados são os canais de distribuição, os tipos de agentes, a função que cada um exerce e a decisão de compra dos varejistas. A pesquisa exploratória foi aplicada a varejistas de pequeno e de médio porte da região de Piracicaba, interior do estado de São Paulo. A partir de oito estudos de caso, foram identificados os aspectos considerados relevantes para os varejistas na decisão de compra e de escolha do tipo de parceiro. Foram apontados pelos varejistas cinco atributos considerados como os mais relevantes, que são: a conveniência, a variedade, o preço, a confiança e a quantidade
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