934 research outputs found
Glycocalyx production in teleosts [Translation from: Verhandlungen der Deutschen Zoologischen Gesellschaft, p.286, 1970]
Shielding the organism against harmful effects from the environment is one of the most important tasks of the outer covering of all animals. The epidermis of primarily aquatic organisms and the epithelia of organs which are exposed to water, such as the digestive or the urinary system, possess a film of glycoproteins and mucopolysaccharides, the glycocalyx. This short paper examines the relationship of the mucus cells with the glycocalyx
Sensitivity to alpha-variation in ultracold atomic-scattering experiments
We present numerical calculations for cesium and mercury to estimate the
sensitivity of the scattering length to the variation of the fine structure
constant alpha. The method used follows ideas Chin and Flambaum [Phys. Rev.
Lett. 96, 230801 (2006)], where the sensitivity to the variation of the
electron to proton mass ratio, beta, was considered. We demonstrate that for
heavy systems, the sensitivity to variation of alpha is of the same order of
magnitude as to variation of beta. Near narrow Feshbach resonances the
enhancement of the sensitivity may exceed nine orders of magnitude.Comment: 5 pages, 1 figur
Enhanced Sensitivity to the Time Variation of the Fine-Structure Constant and in Diatomic Molecules: A Closer Examination of Silicon Monobromide
Recently it was pointed out that transition frequencies in certain diatomic
molecules have an enhanced sensitivity to variations in the fine-structure
constant and the proton-to-electron mass ratio due to a near
cancellation between the fine-structure and vibrational interval in a ground
electronic multiplet [V.~V.~Flambaum and M.~G.~Kozlov, Phys. Rev. Lett.~{\bf
99}, 150801 (2007)]. One such molecule possessing this favorable quality is
silicon monobromide. Here we take a closer examination of SiBr as a candidate
for detecting variations in and . We analyze the rovibronic
spectrum by employing the most accurate experimental data available in the
literature and perform \emph{ab initio} calculations to determine the precise
dependence of the spectrum on variations in . Furthermore, we calculate
the natural linewidths of the rovibronic levels, which place a fundamental
limit on the accuracy to which variations may be determined.Comment: 8 pages, 2 figure
Homogeneous Gold Catalysis through Relativistic Effects: Addition of Water to Propyne
In the catalytic addition of water to propyne the Au(III) catalyst is not
stable under non-relativistic conditions and dissociates into a Au(I) compound
and Cl2. This implies that one link in the chain of events in the catalytic
cycle is broken and relativity may well be seen as the reason why Au(III)
compounds are effective catalysts.Comment: 12 pages, 3 figures, 1 tabl
The convergence of the ab-initio many-body expansion for the cohesive energy of solid mercury
A many-body expansion for mercury clusters of the form E = \sum_{i<j}\Delta
\epsilon_{ij} + \sum_{i<j<k}\Delta \epsilon_{ijk} + ... \quad, does not
converge smoothly with increasing cluster size towards the solid state. Even
for smaller cluster sizes (up to n=6), where van der Waals forces still
dominate, one observes bad convergence behaviour. For solid mercury the
convergence of the many-body expansion can dramatically be improved by an
incremental procedure within an embedded cluster approach. Here one adds the
coupled cluster many-body electron correlation contributions of the embedded
cluster to the bulk HF energy. In this way we obtain a cohesive energy (not
corrected for zero-point vibration) of 0.79 eV in perfect agreement with the
experimental value.Comment: 10 pages, 3 figures, accepted PR
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