Dynamics and rheology of vesicles in a shear flow under gravity and microgravity

International audienceThe behaviour of a vesicle suspension in a simple shear flow between plates (Couette flow) was investigated experimentally in parabolic flight and sounding rocket experiments by Digital Holographic Microscopy. The lift force which pushes deformable vesicles away from walls was quantitatively investigated and is found to be rather well described by a theoretical model by Olla [1]. At longer shearing times, vesicles reach a steady distribution about the center plane of the shear flow chamber, through a balance between the lift force and shear induced diffusion due to hydrodynamic interactions between vesicles. This steady distribution was investigated in the BIOMICS experiment in the MASER 11 sounding rocket. The results allow an estimation of self-diffusion coefficients in vesicle suspensions and reveal possible segregation phenomena in polydisperse suspensions

The use of a shear thinning polymer as a bubbly magma analogue for scaled laboratory experiments

Analogue materials are commonly used in volcanology to perform scaled laboratory experiments. Analogue experiments inform on fundamental fluid dynamic, structural and mechanical processes that are typically very difficult to observe and quantify directly in the natural volcanic system. Here we investigate the suitability of an aqueous solution of hydroxyethyl cellulose polymer (HEC) for use as a lava/magma analogue, with a particular focus on its rheological behaviour. We characterize a range of physical properties as functions of the concentration and temperature of the solution: density; specific heat capacity; thermal diffusivity; thermal conductivity; surface tension; as well as rheology. HEC has a non-Newtonian, shear-thinning rheology that depends on the concentration and temperature of the solution. We show that the rheology is well described by the Cross model, which was originally developed for polymer solutions, but has also been applied to bubbly magmas. Using this similarity, an approach for scaling analogue experiments that use shear-thinning polymers, like HEC, to bubbly magma is presented. A detailed workflow and a spreadsheet are provided to allow experimentalists to investigate the effects of non-Newtonian behaviour in their existing laboratory set-ups. This contribution will allow for the more complex, but often more realistic case of bubble-bearing magmas to be rigorously studied in experimental volcanology

Neutron form factors from elastic electron-deuteron scattering.

http://archive.org/details/neutronformfacto00mad

Transverse-mode coupling effects in scanning cavity microscopy

Tunable open-access Fabry–Pérot microcavities enable the combination of cavity enhancement with high resolution imaging. To assess the limits of this technique originating from background variations, we perform high-finesse scanning cavity microscopy of pristine planar mirrors. We observe spatially localized features of strong cavity transmission reduction for certain cavity mode orders, and periodic background patterns with high spatial frequency. We show in detailed measurements that the localized structures originate from resonant transverse-mode coupling and arise from the topography of the planar mirror surface, in particular its local curvature and gradient. We further examine the background patterns and find that they derive from non-resonant mode coupling, and we attribute it to the micro roughness of the mirror. Our measurements and analysis elucidate the impact of imperfect mirrors and reveal the influence of their microscopic topography. This is crucial for the interpretation of scanning cavity images, and could provide relevant insight for precision applications such as gravitational wave detectors, laser gyroscopes, and reference cavities

K-6 minors in large 6-connected graphs

Jorgensen conjectured that every 6-connected graph with no K-6 minor has a vertex whose deletion makes the graph planar. We prove the conjecture for all sufficiently large graphs. (C) 2017 Published by Elsevier Inc

Umgang mit beruflichen Transitionen: Ergebnisse eines europäischen Forschungsprojektes

Vor dem Hintergrund von Ergebnissen aus dem internationalen Forschungsprojekt "Sozialer Geleitschutz und nachhaltige Beschäftigungsfähigkeit: Innovative Konzepte für Outplacement/Replacement-Beratung" (SOCOSE) werden individuelle berufliche Veränderungen als Transitionen thematisiert. Angesichts instabil werdender Beschäftigungsverhältnisse wurde in fünf Ländern (Belgien, Deutschland, Holland, Italien, Spanien) untersucht, wie Beschäftigte mit Arbeitsplatzunsicherheit und Entlassung umgehen und welche Unterstützungsformen hierbei besonders förderlich sein können. Auf Seiten der Beschäftigten spielten Aspekte des Gerechtigkeitsempfindens eine entscheidende Rolle im Umgang mit (unfreiwilliger) beruflicher Neuorientierung. Darüber hinaus zeigte sich, dass langfristig nur durch eine nachhaltige Kooperation aller Sozialpartner das Ziel einer flexiblen und beschäftigungsfähigen Belegschaft erreicht werden kann.Considering results of the international research project "Social convoy and sustainable employability" (SOCOSE) individual changes of employment are made for subject as occupational transitions. In view of increasing instable conditions of employment structures research was done in five European countries (Belgium, Germany, Netherlands, Italy and Spain). It was investigated how employees deal with insecure job-conditions, with job loss and what kind of support is therefore particularly helpful. On the side of employees aspects of the experience of justice plays an important part in dealing with (unvoluntary) job reorientation. Beyond that it appeared that on the long run we will reach the goal of flexible and employable personnel only through sustainable cooperation between all employers and employed

Inverting the patient involvement paradigm: defining patient led research.

PLAIN ENGLISH SUMMARY: Patients usually understand their disease and lifestyle needs better than many medical professionals. They also have important ideas about what research would be most beneficial to their lives, especially on how to manage symptoms in a way that improves daily quality of life. In the UK, the National Institute for Health Research has recognised the value of patient insight, and now requires researchers with public funding to involve patients and the public throughout the research process. There are many opportunities for involvement, but these generally focus on improving study design to ensure the trial is acceptable to participants. Some programmes work towards setting research priorities as important to patients, public members, and medical experts, but due to the complexity and cost involved in running clinical trials, the majority of research originates with the pharmaceutical industry or academic institutions. There is a clear mismatch between research ideas that patients prioritise (quality of life), and those actually investigated (drug development).The Patient Led Research Hub (PLRH) is a new initiative hosted by the Cambridge Clinical Trials Unit. The PLRH supports research ideas as proposed by patient organisations, providing resources and expertise in research design and delivery. The PLRH aims to co-produce any technically feasible project, regardless of disease or symptom focus. The proposing patient group maintains ownership of the project with an active role in study management. This method of research has proven to produce credible research studies that are of direct relevance to patients. ABSTRACT: Patient and Public Involvement has become an indispensable and expected component of healthcare research in the United Kingdom, largely driven by the National Institute of Health Research and other research funders. Opportunities for patients to become involved in research abound, and many organisations now have dedicated 'public involvement' teams. However, its value is often questioned amidst criticism of tokenism and the recognition that a mismatch persists between patient priorities and funded research. Although patients are frequently consulted, evidence that their involvement influences the research agenda remains limited. We propose a novel model that allows patients and the public not only to propose research questions, but to design, initiate and deliver their own research with all the necessary support from research professionals. We demonstrate the feasibility and utility of this approach in reporting the establishment, experiences and progress of the Patient Led Research Hub. Using this resource, patient organisations are now able to initiate and conduct rigorous clinical research unfettered by the constraints of academic or economic agendas