1,721,065 research outputs found
Pressure effect on water dynamics in tert-butyl alcohol/water solutions
No full textWe report here a quasi-elastic neutron scattering (QENS) investigation of the effect of pressure on the diffusivity properties of water in a dilute aqueous solution of hydrophobic molecules (tert-butyl alcohol, TBA). The experiment was performed at fixed TBA concentration (0.02 molar fraction) by varying pressure from 1 to 2000 bar at two different temperatures (268 and 278 K). The quasi-elastic line-shapes have been analysed in terms of a model based on the memory function formalism. Our data indicate that, on increasing pressure up to 2000 bar, the diffusion coefficient of water in the TBA/water mixture exhibits a relative increase larger than that of pure water under the same thermodynamic conditions. The extent of this effect increases with decreasing temperature. The observed behaviour is described in terms of pressure-induced distortions of the H-bonded random network of liquid water
Electron transfer in dextran probed by longitudinal field muon spin relaxation
No full textElectron-transfer processes play a crucial role in bio-nanobattery design, theelectron transfer rate through the organic material being a key parameter indetermining the resistance, maximum current, power density, discharge rate andduty cycle of the cell. The labelled electron method using positive muons allowssuch transfer processes in macromolecules, such as polymers and proteins, tobe probed on a microscopic level. Here we present the results of an experimentusing the labelled electron method with longitudinal field muon spin relaxation(LF-μSR) to investigate electron-transfer processes in dextran. The data arewell described using the Risch–Kehr model and the results suggest intra-chaindiffusion is the dominant transport process in this systembetween 15 and 250 K.Intra-chain diffusion rates of 1013 s−1 have been determined
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
Molecular mobility: Water-induced hindrance in weakly hydrated polymer systems at low temperature
No full text
Quasi Elastic Neutron Scattering - a tool for the study of biological molecules and processes
No full textVariations 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
- …
