1,720,988 research outputs found
A general conformal-mapping approach to the optimum electrode design of coplanar waveguides with arbitrary cross section
No full text
Acute-phase reactants in acute myocardial infarction: impact on 5-years prognosis
No full textBackground. Acute-phase reactants have recently been shown to have a short-term and possibly long-term prognostic value in acute coronary syndromes. The aim of the present study was to retrospectively verify whether serum levels of inflammation markers can predict the occurrence of early and late cardiac events after myocardial infarction. Methods. We reevaluated 58 consecutive patients (43 men and 15 women, mean age 66 ± 12 years) admitted to our Center during 1993 with a first myocardial infarction. Patients with non-cardiac causes of inflammation were excluded, as well as patients with a left ventricular ejection fraction < 40%. From the first blood sample obtained at admission, we evaluated C-reactive protein (CRP) and α1-acid glycoprotein (α1-AGP) serum levels, the erythrocyte sedimentation rate (ESR), fibrinogen levels, and the white blood cell (WBC) count. We also evaluated the highest level of serum cardiac markers. Follow-up data were collected for 55 patients in June 1999. Results. Five in-hospital and 13 delayed cardiac deaths occurred. The mean follow-up of current survivors was 5.9 ± 0.4 years. Patients in whom cardiac death occurred had significantly higher CRP (7.4 ± 4.1 vs 3.0 ± 2.4 mg/dl, p < 0.001) and α1-AGP levels (160 ± 38 vs 113 ± 24 mg/dl, p < 0.001), ESR (63 ± 30 vs 37 ± 25 mm/hour, p < 0.001), and WBC count (13 727 ± 3853 vs 10 936 ± 3358/mm3, p = 0.004). At multivariate analysis, higher α1-AGP (p < 0.001) and CRP serum levels (p = 0.02) were independent predictors of cardiac death. Patients in whom cardiac events occurred during follow-up showed higher CRP (5.7 ± 3.7 vs 1.6 ± 1.5 mg/dl, p < 0.001) and α1-AGP levels (140 ± 36 vs 101 ± 23 mg/dl, p < 0.001) and ESR (50 ± 30 vs 34 ± 26 mm/hour, p = 0.06). Higher α1-AGP (p < 0.001) and CRP serum levels (p = 0.03) were independent predictors of the occurrence of cardiac events. Conclusions. The present study shows that CRP and α1-AGP have an independent prognostic value in patients presenting with a first, uncomplicated myocardial infarction. Assays of these markers may help to better stratify patients hospitalized for acute coronary syndromes
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
Late ventricular potentials and acute ischemia: study during percutaneous transluminal coronary angioplasty].
No full textIn order to assess if acute ischemia induces ventricular late potentials (VLP), we have studied 35 patients during coronary angioplasty (PTCA), 15 (Group A) with previous myocardial infarction, 20 (Group B) without. VLP detection was performed by standard technique (in the time domain, with Simson algorithm, on 200 beats, using a 25 Hz filter) before, during and 24 hours after PTCA. This procedure was performed on: anterior descending artery (19 cases), circumflex artery (9 cases), right coronary artery (11 cases); four patients had PTCA on two vessels; in Group A patients, PTCA was performed in vessels related to the previous myocardial infarction. VLP were defined as present when at least two of three standard criteria of positivity were detected (QRSD > 115 ms, RMS40 32 ms). In all patients also left ventricular ejection fraction, end diastolic pressure, regional kinesis and amount of myocardium at risk (as measured by the "Duke University jeopardy score") had been assessed. Furthermore, the total and mean inflation time and the degree of induced acute ischemia were also considered. The following results were obtained: no patient had VLP at basal conditions, during PTCA in all patients of both groups we observed a significant prolongation of QRSD but only Group A patients developed VLP, in 56% of cases versus none of Group B. This event was transient: in fact, 24 hours after the procedure VLP were no more present. The two groups did not differ as regards to the values of all the other anatomic and functional above mentioned parameters. Probably the acute ischemia cannot evocate VLP by itself, but this "trigger" needs also a particular substrate with anatomical and functional abnormalities due to a previous myocardial infarction. Further investigations and long follow-up studies are requested to assess if these data could account for the presence of ventricular tachyarrhythmias in patients with acute coronary ischemia and previous myocardial infarction
Interactions Between Reciprocal ST-Segment Downsloping During ST-Elevated Myocardial Infarction and Global Cardiac Perfusion and Functional Abnormalities
No full textReciprocal ST-segment downsloping on electrocardiogram is a frequent finding during ST-elevated myocardial infarction (STEMI), but its etiology is still disputed. We sought to evaluate the relation between reciprocal ST-segment downsloping during STEMI and major cardiac perfusion and functional parameters. One hundred eighty-five patients with STEMI underwent emergency coronary angiography. The presence of reciprocal ST-segment downsloping was assessed. At coronary angiography, the corrected TIMI frame count (cTFC) was computed both on culprit and remote vessels and the occurrence of "no/slow reflow" phenomenon after percutaneous coronary intervention (PCI) identified. The left ventricular wall motion score index ratio (discharge/admission values) at echocardiography and the slope of high-sensitivity troponin elimination were computed as measures of effective myocardial reperfusion. Reciprocal ST-segment downsloping was revealed in 91 patients (49%). They presented higher cTFC values on remote vessels than patients without reciprocal electrocardiographic abnormalities (44 ± 18 vs 37 ± 15 cineframes × second-1, p = 0.004). The presence of remote ST-segment downsloping was also associated with a higher prevalence of "no/slow reflow" phenomenon (59% vs 40%, p = 0.013) as well as more abnormal values of wall motion score index ratio (p = 0.042) and high-sensitivity troponin slope (p = 0.012). At multivariate analyses, a higher cTFC on remote vessels predicted the occurrence of reciprocal ST-segment changes (p = 0.018) and the development of "no/slow reflow" phenomenon after PCI (p = 0.005). In conclusion, the presence of reciprocal ST-segment downsloping during STEMI clusters with significant perfusion and cardiac functional abnormalities, predicting the development of "no reflow" phenomenon after PCI
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
- …
