1,722,488 research outputs found
Just-in-time altimetry: international collaboration in provision of altimetry datasets
Full text linkEnvironmental research requires access to quality controlled, calibrated data. Satellite altimeter data are used in a range of environmental research, including oceanography, ice and land surface studies. Users who are not altimeter specialists may not be aware of, or have access to, the latest updates and most appropriate corrections to use for their application. We propose a GRID based methodology to give all users access to the best possible altimeter data product at the time of the request, tailor made for their specific application. A data portal system would be based on a "Network of Trust" consisting of the data providers and a certificating authority. Data could be served through a fully interactive web 'front-end' or directly from within analysis programmes. This system would build on the experiences gained in combining two existing Altimeter Data services (GAPSand RADS) to produce a coherent data service with alternative web interfaces and configurable users access
Exercise-induced pulmonary hypertension.
No full textExercise stress tests of the pulmonary circulation show promise for the detection of early or latent pulmonary vascular disease and may help us understand the clinical evolution and effects of treatments in patients with established disease. Exercise stresses the pulmonary circulation through increases in cardiac output and left atrial pressure. Recent studies have shown that exercise-induced increase in pulmonary artery pressure is associated with dyspnea-fatigue symptomatology, validating the notion of exercise-induced pulmonary hypertension. Exercise in established pulmonary hypertension has no diagnostic relevance, but may help in the understanding of changes in functional state and the effects of therapies.Journal ArticleSCOPUS: re.jinfo:eu-repo/semantics/publishe
Current perspectives modern hemodynamic evaluation of the pulmonary circulation. Application to pulmonary arterial hypertension and embolic pulmonary hypertension.
No full textThe hemodynamic evaluation of the pulmonary circulation normally includes the measurements of mean pulmonary artery pressure and a calculation of pulmonary vascular resistance (PVR). The definition of PVR can be improved by the measurements of pulmonary vascular pressures at several levels of flow to derive a pressure-flow line, and the site of PVR can be identified by the analysis of pulmonary artery pressure decay curves after balloon occlusion. An analysis of the morphology of pulmonary artery pressure and flow waves informs about right ventricular (RV) hydraulic load. As pulmonary hypertension is clinically a right heart failure syndrome, it is important to measure the coupling of RV to pulmonary arterial function. This can be done using a single beat method with sampling and synchronization of instantaneous pulmonary artery flow and RV pressure to calculate a ratio of end-systolic to arterial elastances. The optimal value of this ratio is depressed in minimally symptomatic pulmonary arterial hypertension patients, indicating pending right heart failure.Journal ArticleReviewinfo:eu-repo/semantics/publishe
Pulmonary Hypertension in Heart Failure: Pathophysiology, Pathobiology, and Emerging Clinical Perspectives
No full textPulmonary hypertension is a common hemodynamic complication of heart failure. Interest in left-sided pulmonary hypertension has increased remarkably in recent years because its development and consequences for the right heart are now seen as mainstay abnormalities that begin in the early stages of the disease and bear unfavorable prognostic insights. However, some knowledge gaps limit our ability to influence this complex condition. Accordingly, attention is now focused on: 1) establishing a definitive consensus for a hemodynamic definition, perhaps incorporating exercise and fluid challenge; 2) implementing the limited data available on the pathobiology of lung capillaries and small arteries; 3) developing standard methods for assessing right ventricular function and, hopefully, its coupling to pulmonary circulation; and 4) searching for effective therapies that may benefit lung vessels and the remodeled right ventricle. The authors review the pathophysiology, pathobiology, and emerging clinical perspectives on pulmonary hypertension across the broad spectrum of heart failure stages.SCOPUS: re.jinfo:eu-repo/semantics/publishe
The overloaded right heart and ventricular interdependence
No full textThe right and the left ventricle are interdependent as both structures are nested within the pericardium, have the septum in common and are encircled with common myocardial fibres. Therefore, right ventricular volume or pressure overloading affects left ventricular function, and this in turn may affect the right ventricle. In normal subjects at rest, right ventricular function has negligible interaction with left ventricular function. However, the right ventricle contributes significantly to the normal cardiac output response to exercise. In patients with right ventricular volume overload without pulmonary hypertension, left ventricular diastolic compliance is decreased and ejection fraction depressed but without intrinsic alteration in contractility. In patients with right ventricular pressure overload, left ventricular compliance is decreased with initial preservation of left ventricular ejection fraction, but with eventual left ventricular atrophic remodelling and altered systolic function. Breathing affects ventricular interdependence, in healthy subjects during exercise and in patients with lung diseases and altered respiratory system mechanics. Inspiration increases right ventricular volumes and decreases left ventricular volumes. Expiration decreases both right and left ventricular volumes. The presence of an intact pericardium enhances ventricular diastolic interdependence but has negligible effect on ventricular systolic interdependence. On the other hand, systolic interdependence is enhanced by a stiff right ventricular free wall, and decreased by a stiff septum. Recent imaging studies have shown that both diastolic and systolic ventricular interactions are negatively affected by right ventricular regional inhomogeneity and prolongation of contraction, which occur along with an increase in pulmonary artery pressure. The clinical relevance of these observations is being explored
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
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