1,720,982 research outputs found
The comparison between MRI and MSCT-enteroclysis in the diagnosis of bowel endometriosis
No full textPurpose: To compare the effectiveness of MRI and MSCT-enteroclysis (MSCTe) in determining the presence of bowel endometriosis (BEM) and the depth of bowel wall infiltration of the nodules. Material and methods: We evaluated 26 women (aged 19–38) with signs and symptoms suggestive of colorectal endometriosis. Patients underwent MRI (1T magnet, phased array coil, multiplanar FSET1, T1 fat sat, T2, T1 post-Gado sequences) and MSCTe (16 rows). The exams were reviewed independently by two radiologists. All women underwent laparoscopy within 2 weeks; radiological findings were compared with surgical and histological data. Statistical analysis was performed with SPSS 13.0. Results: The presence of BEM was detected by MRI in 11 (42.3%) women and by MSCTe in 12 (46.2%). Surgery confirmed BEM in 12 patients identified by MSCTe. In the diagnosis, sensibility, specificity, PPV, NPV were 91.7, 100, 100, 93.3% for MRI and 100, 100, 97, 100% for MSCTe. 21 nodules were identified by MRI and 22 by MSCTe; surgery identified 25 nodules: 13 located on the rectum, 11 at sigmoid colon, and 1 at caecum. One false positive nodule was observed at MSCTe. Among correctly identified nodules, MRI estimated the depth of infiltration to the serosa in 8 cases and to the muscularis in 13. At MSCTe, 4 nodules were judged to infiltrate the serosa, 16 to reach the muscularis propria, and 1 the mucosa. MSCTe correctly estimated the depth of nodules infiltration, significantly more frequently than MRI (p=0.048; Fisher‘s exact test). Conclusion: Both MRI and MSCTe reliably detect the BEM nodules; however, MSCTe is more accurate in estimating the depth of infiltration in the bowel wall
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
Model Predictive Control for Speed Regulation of Autonomous Vehicles at Road Intersections and Performance Evaluation in a V2X Communication Scenario
No full textThe paper aims at evaluating the performance of a centralised control strategy, based on a scheduling procedure and MPC (model predictive control), that regulates the crossing of a four-way intersection by autonomous vehicles avoiding collisions in a V2X (vehicle-to-everything) communication scenario. In particular, we evaluate the performance considering different communication channel gain conditions, with packet loss process implemented through a Bernoullian probabilistic model based on the V2X communication protocol, as well as the impact of transmitting to the vehicles control aggregated commands of multiple future time horizons
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
Three-dimensional in vitro culture of endometrial explants mimics the early stages of endometriosis
No full textOBJECTIVE: To reproduce the earliest phases of endometriosis using a new in vitro model in which cells from a cultured endometrial fragment can proliferate, invade, reconstitute new endometrial-like tissue, and generate blood vessels.
DESIGN: Experimental in vitro study.
SETTING: A hospital-based academic research institute.
PATIENT(S): Five normal ovulating women undergoing surgery for various benign gynecological indications.
INTERVENTION(S): Endometrial samples obtained from the fundus of the uterine cavity were placed in a three-dimensional fibrin matrix culture system.
MAIN OUTCOME MEASURE(S): Degree of proliferation of stromal cells and invasion of the fibrin matrix, gland, and stroma formation, vessel sprouting, and immunohistochemical characterization of various cellular components.
RESULT(S): During the first week of culture, an endometrial cell outgrowth was observed from the original fragments in 120 of 144 wells (83.3%). Subsequently, cell outgrowths could be quantified in 132 (91.6%), 129 (89.5%), and 127 (88.1%) of the wells after 15, 60, and 90 days, respectively. An invasion of the matrix by the human endometrial cells led to the formation of tubular structures that coalesced into tissue, architecturally resembling endometrium and in which the glands were immunohistochemically positive for cytokeratin. New capillaries, immunohistochemically positive for CD31 and vimentin, sprouted from the endometrial outgrowths at the beginning of the fifth week of culture.
CONCLUSION(S): These data show that cells from endometrial explants can proliferate and invade a fibrin matrix in vitro generating new glands, stroma, and vessels consistent with endometriosis. The three-dimensional fibrin matrix used in the present study provides an opportunity to observe the earliest biological events of endometriosis in a quantifiable way
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