Ring-shaped bifocal lens used for fluorescent self-referenced holographic imaging

We propose an alternative and simple solution to self-referenced digital holographic imaging based on a ring-shaped bifocal lens, without the need of any mirrors, polarizers or spatial light modulators. We discuss the imaging properties of the ring-shaped bifocal lens in self-referenced holography. The easy applicability of this bifocal lens is demonstrated on a realized microscope setup for volumetric observation of freely moving fluorescent objects, based on a conventional light microscope

The management of acute venous thromboembolism in clinical practice. Results from the European PREFER in VTE Registry

Venous thromboembolism (VTE) is a significant cause of morbidity and mortality in Europe. Data from real-world registries are necessary, as clinical trials do not represent the full spectrum of VTE patients seen in clinical practice. We aimed to document the epidemiology, management and outcomes of VTE using data from a large, observational database. PREFER in VTE was an international, non-interventional disease registry conducted between January 2013 and July 2015 in primary and secondary care across seven European countries. Consecutive patients with acute VTE were documented and followed up over 12 months. PREFER in VTE included 3,455 patients with a mean age of 60.8 ± 17.0 years. Overall, 53.0 % were male. The majority of patients were assessed in the hospital setting as inpatients or outpatients (78.5 %). The diagnosis was deep-vein thrombosis (DVT) in 59.5 % and pulmonary embolism (PE) in 40.5 %. The most common comorbidities were the various types of cardiovascular disease (excluding hypertension; 45.5 %), hypertension (42.3 %) and dyslipidaemia (21.1 %). Following the index VTE, a large proportion of patients received initial therapy with heparin (73.2 %), almost half received a vitamin K antagonist (48.7 %) and nearly a quarter received a DOAC (24.5 %). Almost a quarter of all presentations were for recurrent VTE, with >80 % of previous episodes having occurred more than 12 months prior to baseline. In conclusion, PREFER in VTE has provided contemporary insights into VTE patients and their real-world management, including their baseline characteristics, risk factors, disease history, symptoms and signs, initial therapy and outcomes

Growth and dissipation of wind forced, deep water waves

International audienceThe input of energy by wind to water waves is compared with the observed growth of the waves using a suite of microphysical measurement techniques in the laboratory. These include measured tangential stresses in the water and air immediately adjacent to the interface with corresponding form drag measurements above wind-forced freely-propagating waves. The drag data sets are consistent but the comparison has highlighted important issues in relation to the measurement of fluctuating pressures above freely-propagating waves. Derived normalised wind input values show good collapse as a function of mean wave steepness and are significantly in excess of the assembly of net wave growth measurements by Peirson and Garcia (2008) at low steepness. Sheltering coefficients in the form of Jeffreys (1925) are derived that are consistent with values previously obtained by Donelan (1987; 1999; 2006). The sheltering coefficients exhibit substantial scatter. By carefully measuring the associated growth of the surface wave fields, systematic energy budgets for the interaction between wind and waves are obtained. For non-breaking waves, there is a significant and systematic misclose in the radiative transfer equation if wave-turbulence interactions are not included. Significantly higher levels of turbulent wave attenuation are found in comparison with the theoretical estimates by Teixeira and Belcher (2002) and Ardhuin and Jenkins (2005). Suitable normalisations of attenuation for wind-forced wave fields exhibit consistent behaviour in the presence and absence of wave breaking. Closure of the surface energy flux budget is obtained by comparing the normalised energy loss rates due to breaking with the values previously determined by Banner and Peirson (2007) and Drazen et al. (2008) when expressed as a function of mean wave steepness. Their normalised energy loss rates obtained for non-wind forced breaking wave groups are remarkably consistent with the levels found during this present study when breaking waves are subject to wind forcing

Vélocimétrie par holographie numérique à deux longueurs d’onde : étalonnage et résultats

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Vélocimétrie par holographie numérique à deux longueurs d’onde : étalonnage et résultats

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Mesure des tourbillons dans un canal à houle par holographie deux couleurs

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Mesure des tourbillons dans un canal à houle par holographie deux couleurs

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