1,720,956 research outputs found
Value of combined cardiopulmonary and echocardiography stress test to characterize the haemodynamic and metabolic responses of patients with heart failure and mid-range ejection fraction
No full textAims
To characterize heart failure (HF) with mid-range ejection fraction (HFmrEF), combining cardiopulmonary exercise test, and exercise stress echocardiography.
Methods and results
We studied 169 consecutive subjects (age 62.3 ± 11 years; 74% male): 30 healthy controls, 45 patients with HF and preserved EF (HFpEF), 40 HFmrEF, and 54 with HF and reduced EF (HFrEF). Left ventricular (LV) stroke volume (SV), EF, elastance, global longitudinal strain, E/E’, oxygen consumption (VO2), and arterial-venous oxygen content difference (AVO2diff) were measured in all exercise stages. HFmrEF revealed baseline features intermediate between HFrEF and HFpEF, except for B-type natriuretic peptide levels, which was similar to HFpEF and significantly lower than HFrEF. Peak VO2 was not significantly different between HF groups. HFrEF exhibited a significantly lower peak SV as compared to either HFpEF or HFmrEF (74.3 ± 21.8 mL vs. 88.0 ± 17.4 mL and 96.5 ± 25.1 mL; P < 0.01), whereas peak heart rate was not significantly different between HF groups. A significantly reduced AVO2diff at peak exercise was apparent in HFpEF and HFmrEF (15.2 ± 3.3 mL/dL and 13.3 ± 4.2 mL/dL) vs. HFrEF (17.±6.6 mL/dL; P < 0.01), whereas no significant difference was reported between HFpEF and HFmrEF. Multivariate analysis in the overall population and all groups revealed peak parameters as independent predictors of peak VO2 (R2 = 0.90, P < 0.0001); AVO2diff showed the largest standardized regression coefficient.
Conclusion
In HFpEF and HFmrEF, effort intolerance is predominantly due to peripheral factors (AVO2diff), whereas in HFrEF peak VO2 is restricted by low increases in SV. Individual therapy according to which component of VO2 is more impaired is advisable
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Diastolic Dysfunction and Left Ventricular Remodeling: classification and prognostic impact of a combined structural and functional echocardiographic analysis in a cohort of patients with Stage A and B Heart Failure with preserved Ejection Fraction (HFpEF)
No full textBackground. Patients with Heart failure with preserved ejection fraction (HFpEF) are characterized by diastolic dysfunction (DD) and adverse left ventricular (LV) remodeling.
Objectives. To assess the prognostic impact of different diastolic function algorithms and a complex remodeling classification (CRC, including relative wall thickness, LV mass index and end-diastolic volume index) in stage A and B HFpEF.
Methods. We selected 1923 stage A and B HFpEF patients (male 43%; age 57, 33-76 years) from a multicenter study, using three algorithms for LV diastolic function (Paulus 2007, Nagueh 2009, Nagueh 2016), with classic and CRC. We considered a composite end-point: all-cause death, hospitalization for worsening HF and acute pulmonary edema.
Results. DD was observed in a minority of the population according to the three different algorithms. The highest presence of DD was diagnosed by Nagueh 2009 (211 patients, 11%), while the prevalence according to Nagueh 2016 (63 patients, 3.3%) turned out to be the lowest (p<0.001 vs the other two algorithms). The proportion of patients with undetermined diastolic function was similar across the 3 algorithms, with a non-significant higher prevalence in Nagueh 2016 (n=154, 8%). According to CRC, 486 (25,3%) patients had adverse hypertrophic remodeling: 294 (15,3%) concentric hypertrophy, 73 (3.8%) eccentric hypertrophy, 80 (4.2%) dilated hypertrophy and 39 (2%) mixed hypertrophy. 294 (15.3%) were unclassifiable. After a median follow-up of 29 months, multivariate Cox-regression (adjusted for age, gender, history of stable ischemic heart disease, classic remodeling classification) identified CRC (p=0.01) and Nagueh 2016 (p<0.001) as independent predictors of end-point. Hypertrophic remodeling patterns (in particular concentric and eccentric hypertrophy) showed the worst prognosis in the survival analysis. The coexistence of an adverse LV remodeling by CRC and DD by Nagueh 2016 was associated with the worst prognosis. CRC succeeded in stratifying also the subgroup with undetermined diastole, proving the coexistence of an adverse hypertrophy pattern is associated with a worse prognosis in these patients.
Conclusions. A concurrent structural (CRC) and functional (Nagueh 2016) analysis improves prognostic stratification in stage A and B HFpEF patients
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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