1,720,968 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
Thyroid autoimmunity and thyroid cancer: further studies on thyroid auto-antibodies, cytology and histology.
No full textDispelling 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
Autoimmunità e neoplasie della tiroide: studio citologico, ecografico ed istologico.
No full textINTRODUZIONE: L’associazione tra tiroidite cronica linfocitaria e carcinoma papillare della tiroide è stata segnalata in vari lavori, ma è tuttora oggetto di discussione per i risultati contrastanti ottenuti con diversi approcci metodologici. SCOPO DEL LAVORO: Scopo del presente lavoro è stato quindi di valutare l’associazione tra autoimmunità e neoplasie tiroidee mediante analisi multivariata di vari parametri. In particolare, in 207 pazienti con patologia nodulare sottoposti a tiroidectomia sono stati retrospettivamente valutati: a) esame citologico ed esame istologico; b) presenza di anticorpi antitiroide (ATA), ipoecogenicità parenchimale (IE) e infiltrato linfocitario perinodulare (IL), come parametri di autoimmunità tiroidea. Per l’esame citologico sono state prese in considerazione le seguenti classi: II (citologia benigna), III (citologia indeterminata) e IV (sospetta o certa per malignità). Per l’esame istologico sono stati considerati gli istotipi: adenoma follicolare (AF), carcinoma papillare (KP) e carcinoma follicolare (KF).
RISULTATI: I risultati ottenuti hanno mostrato una prevalenza significativamente aumentata di citologia di classe IV e di carcinomi papillari nei noduli ATA+. Un aumento significativo dell’incidenza di carcinomi papillari, ma non di citologia di classe IV, era osservata nei noduli con infiltrato linfocitario parenchimale. Nessuna associazione tra citologia e/o istologia benigna o maligna era invece rilevata con l’ecogenicità parenchimale, nonostante che la presenza di parenchima ipoecogeno fosse osservata nella larga maggioranza dei noduli ATA+ (74,4%) o associati ad infiltrato linfocitario (79,5%).
CONCLUSIONI: In conclusione, il presente lavoro conferma una significativa associazione tra carcinoma papillare della tiroide ed autoimmunità tiroidea, in particolare presenza di ATA+. L’associazione è risultata meno evidente con gli infiltrati linfocitari e nulla con l’ecogenicità parenchimale. Questo rilievo suggerisce che nel carcinoma papillare sia spesso presente una reazione autoimmune secondaria piuttosto che una reale associazione con la tiroidite di Hashimoto
Thyroid autoimmunity and throid tumors: results of a echographic, cytological and histological study.
No full textOBJECTIVE: The association between chronic lymphocytic thyroiditis or Hashimoto’s thyroiditis (HT) and papillary thyroid carcinoma (PTC) has been suggested by surgical studies, but it is difficult to prove due to the contrasting results obtained with different methodological approaches. Aim of this study was to evaluate the association between HT and thyroid neoplasias comparing several diagnostic parameters by an univariate analysis. PATIENTS AND METHODS: In a total of 207 patients with nodular thyroid disease who underwent to thyroidectomy, we retrospectively compared: a) cytological and histological results, b) presence of anti-thyroid autoantibodies (ATA), tissue hypoecogenicity at ultrasound esamination (USH) and lymphocytic thyroid infiltration (LTI), as parameters of thyroid autoimmunity. Cytology were classified in three classes of increased risk of malignancy: benign (class II); mild increased risk (class III) and suspect or malignant (class IV) nodules. Histological diagnoses were: follicular adenoma (FA), follicular carcinoma (FC) and PTC. RESULTS: As displayed in the Table, when presence/absence of thyroid autoimmune parameters were considered, a significantly increased prevalence of class IV cytology and PTC in ATA+ nodules were found. A significantly increase prevalence of PTC and an high parevalence of class IV cytology was also observed in thyroid nodules associated to LTI. These results were also confirmed when the highest ATA titres and diffuse LTI were considered. Although USH correlated with the presence of ATA and LTI, no association between USH, cytological and histological results was found.
Our study confirmed a significant association between PTC and thyroid autoimmunity, in particular with ATA postivity and diffuse LTI. The analysis of ATA titres and LTI pattern provide evidence that this relationship may be considered as a true association instead a secondary autoimmune reaction
High prevalence of suspicious cytology in thyroid nodules associated with positive thyroid autoantibodies
No full textObjective: The association between thyroid autoimmunity and thyroid cancer has been often suggested, but is difficult to prove due to selection bias of surgical series. Aim of this study was then to re-assess this association in a retrospective series of unselected thyroid nodules submitted to fine needle aspiration cytology (FNAC).
Subjects and methods: We reviewed 590 ultrasound (US) guided FNACs obtained from unselected consecutive single thyroid nodules referred to our outpatient service from January 2002 to July 2004.
Cytological results were classified in three classes of increased risk of malignancy: low risk or benign (class II); mild increased risk (class III) and suspect or malignant (class IV) nodules. Cytological results were analyzed according to the presence (ATA+ n=197) or absence (ATA- n=393) of associated serum anti-thyroid antibodies (ATA) as marker of thyroid autoimmunity.
Results: The distribution of cytological classes within the study groups was as follows: Group ATA-: class II n=273 (69.5%), class III n=84 (21.4%) and class IV n=36 (9.2%); Group ATA+: class II n=103 (52.3%), class III n=57 (28.9%) and class IV n=37 (18.8%), corresponding to a significantly higher prevalence of class III (p<0.05) and class IV (p<0.001) in ATA+ nodules. The prevalence of class II nodules was significantly lower (p<0.001) in ATA+ patients. In 106 patients submitted to thyroidectomy, thyroid cancer was found in 54/61 (88.5%) patients with class IV cytology (without significant difference between ATA+ [96.4%] and ATA– [81.8%] nodules), and in 6/31 (19.3%) of class III nodules, exclusively in ATA-. Taken together, higher cancer prevalence, mostly represented by papillary thyroid carcinoma, was documented in ATA+ (27/197=13.7%), when compared to ATA– nodules (33/393=8.4%, p<0.05).
Conclusions: The present study, performed on unselected consecutive thyroid FNACs, devoid of selection biases, showed increased frequency of suspect or clearly malignant FNACs in ATA+ nodules when compared to ATA-. According to histological results, this finding was not due to false positive FNACs and is in keeping with previous studies supporting a significant association between papillary thyroid carcinoma and thyroid autoimmunity
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