1,720,975 research outputs found
Dispersive QPM-SHG from /spl chi//sup (2)/ nonlinear photonic crystal LiNbO/sub 3/with tetragonal symmetry
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Regional cingulum disruption, not gray matter atrophy, detects cognitive changes in amnestic mild cognitive impairment subtypes
No full textAmnestic mild cognitive impairment (aMCI), which has a high risk of progression to Alzheimer's disease (AD), can be classified into single domain (S-aMCI) and multiple domain (M-aMCI) subtypes. We investigated the integrity of regional gray matter and segments of the cingulum bundle with diffusion spectrum imaging tract-specific analysis, and their relationships to neuropsychological functioning, in 46 individuals with aMCI (S-aMCI n = 24; M-aMCI n = 22) and 36 healthy controls (HC). Results demonstrated that although both aMCI groups were impaired on all memory measures relative to HCs, the M-aMCI group demonstrated worse performance on paired association memory and on selective executive function relative to the S-aMCI group. The two aMCI groups did not show significant atrophy in regional gray matter indices as compared to the HC group, but the M-aMCI group showed significant disruption in white matter of the left anterior and inferior cingulum bundles relative to the S-aMCI and HC groups. Furthermore, disruption in the inferior cingulum bundles was significantly associated with executive function and attention/processing speed in all aMCI participants above and beyond the contribution of bilateral hippocampal volumes. Overall, these results indicate that the degeneration of cingulum fibers did not appear to arise from degeneration of the corresponding cerebral cortex. It also suggests relatively greater sensitivity of a white matter biomarker and comprehensive neuropsychological evaluation over gray matter biomarkers in early detection of AD
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
A Needs Assessment of Personalized Serviceon the University Library Website
No full text電子出版的成熟以及網際網路的盛行，使得網路上的資訊以驚人的速度成長。使用者在取用圖書館網站大量的電子資源和各項服務內容時，面臨了資訊超載的問題。為幫助使用者過濾資訊，減輕資訊超載之壓力，大學圖書館開始在網站上發展個人化服務。但圖書館網站發展個人化服務必須花費相當多的時間、人力與金錢。本研究之目的在於探討大學圖書館網站使用者對圖書館網站個人化服務之需求內容及需求程度，以及進一步探討使用者對圖書館網站個人化服務需求之影響因素。問卷調查結果顯示，學生傾向於需要個人化服務，但大學部學生與研究所學生之間有顯著的差異。Almost all university libraries increase their print and electronic resources in past decades. At the same time, libraries provide more and more services on their websites. Facing the growth of information and services, it seems that library users will need some kinds of filtering mechanism. A few university library websites initiate personalized service. But, do university library users need the service? What kind of services do they need? Questionnaire survey is made in this study. Results indicate that the students appreciate personalized service, but there is a significant difference between undergraduate students and graduate students
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
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