1,720,996 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
Detailed pathologic characteristics of the primary colorectal tumor independently predict outcome after hepatectomy for metastases.
No full textDetailed Analysis of Margin Positivity and the Site of Local Recurrence After Pancreaticoduodenectomy
No full textBackground. The association between a positive surgical margin and local recurrence after resection of pancreatic adenocarcinoma (PDAC) has been reported. Assessment of the location of the a positive margin and the specific site of local recurrence has not been well described. Methods. A prospectively maintained database was quer- ied for
patients who underwent R0/R1
pancreaticoduodenectomy for PDAC between 2000 and 2015. The pancreatic, posterior, gastric/duodenal, anterior peritoneal, and bile duct margins were routinely assessed. Postoperative imaging was reviewed for the site of first recurrence, and local recurrence was defined as recurrence located in the remnant pancreas, surgical bed, or retroperitoneal site outside the surgical bed. Results. During the study period, 891 patients underwent pancreaticoduodenectomy, and 390 patients had an initial local recurrence with or without distant metastases. The 5-year cumulative incidence of local recurrence by site included the remnant pancreas (4%; 95% confidence interval [CI], 3–5%), the surgical bed (35%; 95% CI, 32–39%), and other regional retroperitoneal site (4%; 95% CI, 3–6%). In the univariate analysis, positive posterior margin (hazard ratio [HR], 1.50; 95% CI, 1.17–1.91; p = 0.001) and positive lymph nodes (HR, 1.36; 95% CI, 1.06–1.75; p = 0.017) were associated with surgical bed recurrence, and in the multivariate analysis, positive pos- terior margin remained significant (HR, 1.40; 95% CI, 1.09–1.81; p = 0.009). An isolated local recurrence was found in 197 patients, and a positive posterior margin was associated with surgical bed recurrence in this subgroup (HR, 1.51; 95% CI, 1.08–2.10; p = 0.016). Conclusion. In this study, the primary association between site of margin positivity and site of local recurrence was between the posterior margin and surgical bed recurrence. Given this association and the limited ability to modify this margin intraoperatively, preoperative assessment should be emphasized
Perioperative Bundle to Reduce Surgical Site Infection after Pancreaticoduodenectomy: A Prospective Cohort Study
No full textBACKGROUND:
Pancreaticoduodenectomy is historically associated with incisional surgical site infection (iSSI) rates between 15% and 20%. Prospective studies have been mixed with respect to the benefit of individual interventions directed at decreasing iSSI. We hypothesized that the application of a perioperative bundle during pancreaticoduodenectomy would decrease the rate of iSSIs significantly.
METHODS:
An initial cohort of 150 consecutive post-pancreaticoduodenectomy patients were assessed within 2 to 4 weeks of operation to determine baseline iSSI rates. The CDC definition of iSSI was used. A 4-part perioperative bundle was then instituted for the second cohort of 150 patients. This bundle consisted of a double-ring wound protector, gown/glove and drape change before fascial closure, irrigation of the wound with bacitracin solution, and a negative-pressure wound dressing that was left in place until postoperative day 7 or day of discharge. Three-hundred patients provided 80% power to detect a 50% risk reduction in iSSIs.
RESULTS:
Cohorts 1 and 2 were similar with respect to age (68 vs 69 years; p = 0.918), sex (male, 51% vs 55%; p = 0.644), BMI (26 vs 26 kg/m2; p = 0.928), use of neoadjuvant therapy (21% vs 17%; p = 0.377), median operative time (222 vs 215 minutes; p = 0.366), and presence of a preoperative stent (53% vs 41%; p = 0.064). The iSSI rate was 22.3% in the initial cohort. This rate was higher than both our institutional database (13%) and NSQIP reporting (11%). Within the second cohort, the iSSI rate decreased significantly to 10.7% (n = 16; p = 0.012). All 4 components of the bundle were used in 91% of cohort 2 patients.
CONCLUSIONS:
In this cohort study of 300 consecutive patients who underwent pancreaticoduodenectomy, the implementation of a 4-part bundle decreased iSSI rate from 22% to 11%
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
Neutrophil-to-Lymphocyte Ratio as a Predictor of Invasive Carcinoma in Patients With Intraductal Papillary Mucinous Neoplasms of the Pancreas
No full textObjectives Preoperative determination of the grade of dysplasia in intraductal papillary mucinous neoplasms (IPMNs) is necessary for optimal management. Previous data have suggested that serum neutrophil-to-lymphocyte ratio (NLR) can predict invasive disease in patients with IPMN. Methods A prospectively maintained database was queried for consecutive patients who underwent resection of IPMN. Exclusion criteria included recent diagnosis of cancer, immunosuppression, and infection or jaundice within 1 month of operation. A complete blood count with differential within 30 days of operation was used to calculate NLR. Results Within the study period, 446 patients underwent resection for IPMN, and 348 patients (78%) met the inclusion criteria. Low-grade dysplasia was present in 60 patients (17%), 137 patients (39%) had intermediate-grade dysplasia, 76 (22%) had high-grade dysplasia, and 75 (22%) had invasive carcinoma. A higher NLR was associated with invasive carcinoma as compared with noninvasive disease (3.00 vs 2.68, P = 0.039). There was no difference in NLR between patients with high-risk (invasive and high-grade) and low-risk (low-grade and intermediate-grade) lesions (2.80 vs 2.71, P > 0.95). Conclusions Neutrophil-to-lymphocyte ratio was significantly higher in patients with IPMN-associated invasive carcinoma as compared with patients with noninvasive disease; however, NLR was not helpful in differentiating between high- and low-grade lesions
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