Racial disparities in early mortality in 1,134 young patients with acute stroke

10.1007/s10072-014-1640-9Neurological Sciences3571041-1049NESC

A study of the swelling of copolymers of NIPAM and DMA with water by NMR imaging

A range of copolymers of N-isopropylacrylamide and N,N-diniethylacrylamide (DMA) have been prepared and the properties of these materials in aqueous solution examined by nuclear magnetic resonance (NMR) imaging. All of the polymers apart from PDMA exhibit a lower critical solution temperature, with the temperature and width of the transition increasing with increasing DMA content. On exposure to water the polymers swell rapidly; the kinetics of mass uptake are seen to closely resemble those expected for Fickian kinetics, although the Frisch exponents are slightly larger than expected. NMR imaging however reveals that the diffusion of water into these polymers is highly anoinalous, With concentration profiles more typical of Case It diffusion. The deformation model of Thomas and Windle was used to analyze the water content profiles, and the resultant parameters used in the fits related to the structure of the two constituent monomer units

Data in Antarctic science and politics

The internationalization of Antarctica as a continent for science with the Antarctic Treaty (1961) was heralded as bringing about international cooperation and the free exchange of data. However, both national rivalry and proprietorship of data, in varying degrees, remained integral to Antarctic science and politics throughout the 20th century. This paper considers two large field-surveys in Antarctica: first, an aerial photographic survey carried out by the Ronne Antarctic Research Expedition of 1946—8; and second, the Scott Polar Research Institute's radio-echo sounding survey of 1967—79. Both surveys involved geoscientific data but the context in which the investigations and the exchanges of their results took place changed. We argue that the issue of control of data remained paramount across both cases despite shifting international political contexts. The control of data on Antarctic territory, once framed in terms of geopolitics and negotiated between governments, became a matter of science policy and credit to be negotiated among scientific institutions. Whereas the Ronne data were of potential strategic value for reinforcing national territorial claims, the radio-echo sounding data contained information of potential economic and environmental value