18,692 research outputs found
Quantum Evolution of Inhomogeneities in Curved Space
We obtain the renormalized equations of motion for matter and semi-classical
gravity in an inhomogeneous space-time. We use the functional Schrodinger
picture and a simple Gaussian approximation to analyze the time evolution of
the model, and we establish the renormalizability of this
non-perturbative approximation. We also show that the energy-momentum tensor in
this approximation is finite once we consider the usual mass and coupling
constant renormalizations, without the need of further geometrical
counter-terms.Comment: 22 page
Literacy: A cultural influence on functional left-right differences in the inferior parietal cortex
The current understanding of hemispheric interaction is limited. Functional hemispheric specialization is likely to depend on both genetic and environmental factors. In the present study we investigated the importance of one factor, literacy, for the functional lateralization in the inferior parietal cortex in two independent samples of literate and illiterate subjects. The results show that the illiterate group are consistently more right-lateralized than their literate controls. In contrast, the two groups showed a similar degree of left-right differences in early speech-related regions of the superior temporal cortex. These results provide evidence suggesting that a cultural factor, literacy, influences the functional hemispheric balance in reading and verbal working memory-related regions. In a third sample, we investigated grey and white matter with voxel-based morphometry. The results showed differences between literacy groups in white matter intensities related to the mid-body region of the corpus callosum and the inferior parietal and parietotemporal regions (literate > illiterate). There were no corresponding differences in the grey matter. This suggests that the influence of literacy on brain structure related to reading and verbal working memory is affecting large-scale brain connectivity more than grey matter per se
Biodegradable polymeric fiber structures in tissue engineering
Tissue engineering offers a promising new approach to create biological alternatives to repair or restore function
of damaged or diseased tissues. To obtain three-dimensional tissue constructs, stem or progenitor cells must be
combined with a highly porous three-dimensional scaffold, but many of the structures purposed for tissue engineering
cannot meet all the criteria required by an adequate scaffold because of lack of mechanical strength and
interconnectivity, as well as poor surface characteristics. Fiber-based structures represent a wide range of morphological
and geometric possibilities that can be tailored for each specific tissue-engineering application. The
present article overviews the research data on tissue-engineering therapies based on the use of biodegradable fiber
architectures as a scaffold
The impact of ancestral population size and incomplete lineage sorting on Bayesian estimation of species divergence times
MdR was supported by Biotechnology and Biological Sciences Research Council (UK) grant BB/J009709/1 awarded to ZY
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