1,720,965 research outputs found
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
Mean Kurtosis discriminates between low- and high-risk prostate cancer better than mean diffusivity does
No full textSynopsis
This work was finalized to compare the diagnostic potential of Diffusion Tensor and Diffusion Kurtosis Imaging in discriminating between low- and high-risk prostate cancer (Pca). Maps of Mean Diffusivity (MD), apparent Kurtosis (K) and apparent diffusion coefficient (D) were obtained from DWIs of 24 patients with different tumour grade. K maps better highlight differences between periferal PCa, PCa and benign tissue. In particular K discriminates between low- and high-risk PCa with a higher statistical significance compared to that of MD. DKI can improve the accuracy of the current PCa diagnosis providing a useful tool for PCa detection and grading.
Purpose
Prostate cancer (PCa) is the second most common malignancy and the fifth leading cause of death in men worldwide [1]. Accurate staging is desirable for treatment planning, since high-risk cancer is treated with surgery or radiation, while therapy for low-risk cancer considers active surveillance without invasive treatments. According to the new grading system proposed by the ISUP [2], low risk PCa are characterized by Grade Group (GG)=1,2 while high risk PCa are defined by GG≥
3. Diffusion Tensor Imaging (DTI) with high b-values (up to 2500s/mm2) has highlighted to provide a good discrimination between low- and high-risk PCa [3]. However, parameters derived from non-Gaussian diffusion model are in principle more sensitive to the microstructural changes in biological tissue than the Gaussian model [4]. Therefore, our aim was to compare the diagnostic performance of diffusional kurtosis imaging (DKI) and the conventional DTI approach in the discrimination between low- and high-risk PCa.
Materials and Methods
A cohort of 24 patients with different aggressiveness grades (GG=1,2,3,4,5 corresponding to Gleason Score GS=3+3,3+4,4+3,4+4,4+5/5+4) PCa were retrospectively enrolled to be examined by MRI, using a 3T clinical MR scanner (Intera Achieva, Philips Medical Systems, The Nederlands) and a six-channel phased array SENSE torso coil. Each patient underwent the MR examination after two months from the first TRUS-guided biopsy. Diffusion-weighted images were acquired along 6 different diffusion directions with 6 different b-values (0,500,1000,1500,2000,2500 s/mm2), by using a diffusion weighted single shot EPI sequence (TR=3000, TE=67, FOV=150×130×70mm3, acquisition matrix=64×52, reconstruction matrix 96×96, slice thickness STK=3mm, gap=0, NSA=4). The acquisition protocol also included high spatial resolution T2-weighted (T2W) turbo spin echo (TR=3957, TE=150, turbo factor 21, FOV=150×130mm, STK=3mm, gap=0, acquisition matrix256x178, reconstruction matrix=512×512, NSA=6, flip angle=90°). The image pre-processing and the reconstruction of the Mean Diffusivity (MD) parametric maps was performed using FSL 5.0 (FMRIB Software Library v5.0, FMRIB, Oxford, UK). Parametric maps of apparent Kurtosis (K) and apparent diffusion coefficient (D) of the quadratic model were obtained by using an in-house algorithm developed in Matlab (MATLAB R2012b, The Mathworks, Natick, MA). Region of Interests (ROI) in PCa and contralateral benign zone were manually drawn by an expert radiologist, referring to T2W-images, for each subject. The pixels nearest to the PCa ROI edge were considered as peritumoral ROI. One-way ANOVA was performed to test statistical significance of differences in MD, K and D values calculated in PCa belonging to low- and high-grade groups. Moreover, the statistical significance of differences in MD, K and D values between benign and PCa tissue and between benign and peritumoral area were evaluated. The linear correlation between MD, K, D values and the tumour grade was estimated by the Pearson's test. Because low Signal to Noise Ratio (SNR) of DWIs acquired at larger b-values are an obvious drawback for non Gaussian diffusion techniques, we evaluated SNR of DWIs at each b values to investigate about the reliability DKI maps.
Results
An example of T2, MD, K and D maps are displayed in Fig.1 for a patient with PCa characterized by GG=3. The SNR of b=0 images was approximately equal to 55 in PCa and remained higher than 22 up to b=2500 s/mm2. Statistically significant difference was found between each parameter values (MD, K, D) measured in PCa and benign controlateral zone. However, K had the highest significance (p<0.0001). K showed the highest significance (p<0.001) also in the discrimination between peritumoral and benign regions and peritumoral and PCa. A moderate positive correlation was found between K and GG (r=0.52; p<0.001), while a weak negative correlation was found between both D and MD and GG (r=-0.38, p=0.011; r=-0.36, p=0.016, respectively). Plots of K, D and MD as a function of GG are displayed in Fig.2. K, D and MD significantly discriminate between low-risk (GG=1&2) and high-risk PCa (GG=3,4,5) with p<0.001, p<0.004, p<0.02, respectively.
Discussion and conclusions
The SNR was higher than 20, which is an acceptable value for considering DKI maps reliable. The diagnostic performance of DKI in discriminating between PCa and benign tissue and in differentiating among PCa characterized by different GG was superior compared to that provided by DTI. Moreover K maps better highlight differences between periferal PCa and benign tissue. In particular K discriminates between low- and high-risk PCa better than Mean diffusivity does (Fig.2).
These results confirm that non-Gaussian DKI parameters are more sensitive to tissue microstructural changes, occurring with tumour onset and progression compared to Gaussian parametrs. Therefore this work suggests that DKI could be a useful tool in the diagnosis and grading of PCa to ensure a correct therapy for the patients. References
[1] Ferlay, J. et al., Cancer incidence and mortality worldwide: Sources, methods and major patterns in GLOBOCAN 2012. Int. J. Cancer, 136 (2015): E359–E386.
[2] J.I. Epstein et al. The grading committee, the 2014 International Society of Urological Pathology (ISUP) consensus conference on gleason grading of prostatic carcinoma: definition of grading patterns and proposal for a new grading system. Am. J. Surg. Pathol., 40 (2) (2016), pp. 244–252.
[3] Nezzo, M. et al., Mean diffusivity discriminates between prostate cancer with grade group 1&2 and grade groups equal to or greater than 3. European Journal of Radiology , Volume 85 (2016) , Issue 10 , 1794 – 1801.
[4] Jensen JH, Helpern JA. MRI quantification of non-Gaussian water diffusion by kurtosis analysis. NMR Biomed 2010;23:698– 710
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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