1,720,990 research outputs found
Evaluation of Sensitivity and Reliability of FunctionalR Spectroscopy Using Virtual Titration
No full text核磁共振頻譜可以非侵入式的方式提供人體內化學物質的資訊。將它和功能性磁振造影的觀念結合後，功能性磁振頻譜已經成為研究神經生理學時一項有力的工具。然而，已有報告指出譜線的特性會受到血氧程度相關效應的影響，而這對於代謝物濃度定量所造成的影響尚未被完整地評估。但在功能性詞振頻譜的研究中，研究者感興趣的就是濃度的微小改變，因此這個影響可能是很關鍵性的。在這個研究中，我們模擬了13個頻譜裡肌酸、膽鹼與N-acetyl-L-aspartic acid的微小濃度改變，以評估線性疊加模型軟體(一個磁振頻譜定量軟體)的靈敏度與穩定度。此外，我們模擬了可能因為血氧程度相關效應所造成的線寬改變，以檢驗定量結果是否會受到影響。我們的結果顯示，三種代謝物在濃度改變超過±0.8%即可被偵測到，但對於肌酸和膽鹼，真實的濃度改變可能會被高估。此外，在高信雜比的條件下，線寬造成三種代謝物一致的濃度改變，但在有雜訊的情況下，各頻譜間的濃度改變有很大的差異。我們的結論是，線性疊加模型軟體對於微小的濃度改變敏感，但需要發展一個校正的流程以消除偽濃度改變量。Magnetic resonance spectroscopy (MRS) can be used to provide chemical information within human body noninvasively. Combining it with the concept of functional magnetic resonance in imaging (fMRI), functional magnetic resonance spectroscopy (fMRS) has become a powerful tool to investigate neural physiology. However, it has been reported that spectral line properties can be affect by blood-oxygenation-level-dependent (BOLD) effect, and the resultant impact on metabolite quantification has not yet been thoroughly evaluated. But this impact could be critical since in fMRS studies, the tiny changes of the concentrations are of interest. In this study, we simulated tiny concentration changes of creatine, choline, and N-acetyl-L-aspartic acid of 13 spectra to evaluate the sensitivity and reliability of LCModel (MRS quantification software). In addition, we simulated linewidth alterations that could result from BOLD effect, to examine whether the quantification result will be affected or not. Our result shows that concentration changes exceeding ±0.8% could be detectable for the three metabolites, but the actual concentration change may be over-estimated when quantifying creatine and choline. Besides, linewidth alterations result in consistent concentration changes for the three metabolites under the condition of high SNR. But in the presence of noise, results of concentration changes shows large variations among spectra. We conclude that LCModel is sensitive to tiny concentration changes, but it would be necessary to develop a calibration procedure to eliminate pseudo concentration changes.Chapter 1 Introduction to Proton Magnetic Resonance Spectroscopy.1 Background......................................................1.2 Quantification Method...........................................1.3 From conventional MRS to Functional MRS.........................4.4 Motives.........................................................5hapter 2 Materials and Methods .1 MRS Data........................................................7.2 LCModel Basis...................................................9.3 LCModel Settings................................................9.4 Simulation of the In Vivo Spectrum.............................12.5 Virtual Titration..............................................17.6 Statistical Analysis...........................................19hapter 3 Results .1 Virtual Titration: Concentration Change and Estimation Error...21.2 Virtual Titration: Linewidth Alteration........................29.3 The “Noise”..................................................33hapter 4 Discussions and Conclusions .1 Concentration Change...........................................35.2 Linewidth Alteration...........................................36.3 On Simulation Procedure........................................37.4 Some Notes for Functional MRS Studies..........................38.5 Conclusion.....................................................39eferences.........................................................4
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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