1,720,986 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
Persistently High Levels of Coagulation Factor XI as a Risk Factor for Venous Thrombosis
Full text linkCoagulation factor XI (FXI) promotes fibrin formation and inhibits fibrinolysis. Elevated plasma FXI levels, limited to a single measurement, are associated with a higher thrombotic risk. Our case-control study aimed to identify the effect of persistently increased plasma FXI levels on the risk of deep vein thrombosis (DVT). All patients evaluated between January 2016 and January 2018 for a first episode of proximal DVT of the lower extremity were considered for enrolment. Plasma FXI levels were measured at least 1 month after the discontinuation of anticoagulant treatment (T1). The patients with increased plasma FXI levels (>90th percentile of controls) were tested again 3 months later (T2). Among the 200 enrolled patients (M/F 114/86, age range 26-87 years), 47 patients had increased plasma FXI levels at T1 and16 patients had persistently increased plasma FXI levels at T2. The adjusted odds ratio for DVT was 2.4 (95% CI, 1.3 to 5.5, p < 0.001) for patients with increased FXI levels at T1 and 5.2 (95% CI, 2.3 to 13.2, p < 0.001) for patients with persistently high FXI levels at T2. Elevated FXI levels constitute a risk factor for deep vein thrombosis, and this risk nearly doubled in patients with persistently increased plasma FXI levels. Larger prospective studies are needed to confirm our findings
Mechanisms of thrombosis in pancreatic ductal adenocarcinoma
No full textPatients with pancreatic cancer have a very high risk of both venous and arterial thrombosis compared with other cancers, caused by a tumour-driven hypercoagulable state. Better understanding of pancreatic cancer-associated prothrombotic and proinflammatory mechanisms opens the door to controlling prothrombotic states, ideally, without affecting the overall haemostasis. This narrative review brings together currently available evidence on epidemiology and pathogenesis of thrombotic complications in pancreatic adenocarcinoma. We describe risk factors for thrombosis and established and novel mechanisms of hypercoagulability. Among novel pathways of hypercoagulability, the release of neutrophils extracellular traps (NETs) by activated neutrophils and the crucial role of extracellular vesicles (EV) in participating in platelet and coagulation activation were described. We also reported recent evidence on EV role in thrombin generation amplification through the activation of the intrinsic pathway, discussing potential molecules implicated in this process
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
Prothrombotic risk factors in pregnancy
No full textPregnancy and puerperium have historically been associated with a significant increase – five-and tenfold vs non-pregnant women, respectively – of the thromboembolic risk, which in turn is the main cause of maternal mortality. Predisposing factors for thrombosis include components of the so-called Virchow’s triad: venous stasis, hypercoagulability and endothelial damage/dysfunction. Venous stasis is secondary to the compression that the uterus exerts on the inferior vena cava and the pelvic veins, to the reduction of the progesterone-mediated venous tone and to the development of varicose veins in the lower limbs; and, sometimes, to a prolonged immobilization. Furthermore, there is a physiological tendency to hypercoagulability, caused by an imbalance between procoagulant and anticoagulant factors, which on the one hand counters the postpartum hemorrhagic risk, while on the other increases the thromboembolic risk. The hypercoagulable profile may be confirmed via global coagulation assessment tests, such as thrombin generation and thromboelastometry/-graphy. The presence of a thrombophilic state – the tendency to develop thrombosis from an inherited or acquired condition – may contribute, alone or in association with other compounding factors, to the added thrombotic risk described in pregnancy. Pregnancy, especially if complicated, also involves endothelial activation, which may trigger thrombotic events, as confirmed by the increased levels of various plasma markers. Finally, the Virchow’s triad is often exacerbated by several thrombotic risk factors, such as a personal history of venous thrombosis, advanced age, obesity, plurality, smoking, hypertension, blood group A and caesarean section
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
Mucocele della cistifellea in un cane
No full textSi descrive in un cane Schnauzer nano maschio di 8 anni un caso di mucocele della cistifellea, rara condizione caratterizzata da distensione della cistifellea per accumulo abnorme di muco. La patologia, diagnosticata in vita tramite esame ecografico (sovradistensione della cistifellea con materiale anecogeno riferibile a muco lungo le pareti e bile iperecogena con pattern stellato al centro della cavità) è stata trattata chirurgicamente con colecistectomia. La terapia ha risolto completamente il caso e l’esame anatomoistopatologico ha confermato la diagnosi (iperplasia e displasia cistica della mucosa della cistifellea con abbondante produzione di muco denso). Vengono passate in rassegna le principali ipotesi eziopatogenetiche del mucocele della cistifellea
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
- …
