The effects of salinity and osmolality differences on the uptake rates of dissolved zinc were investigated in 3 crabs of different ecologies -the euryhaline common shore crab Carcinus maenas, the extremely euryhaline Chinese mitten crab Eriocheir sinensis, and a more stenohaline marine crab, the velvet swimming crab Necora puber. Reduced salinities caused increases in the zinc uptake rate of E. sinensis as expected from the free metal ion model, with increased free zinc ion availabilities in conditions of reduced chloride complexation. In the cases of C. maenas and N. puber, however, reduced salinity was associated with reduced zinc uptake, a result interpreted in terms of a physiological response by these crabs to low salinity offsetting the physicochemical effect of increased free zinc ion availability. Results can be partly explained by reported changes in apparent water permeability (AWP) made by the crabs to low salinity, although experiments manipulating solution osmotic pressures independently of salinity (and therefore chloride concentrations) indicate that other physiological responses may also be coming into effect. The interaction of physiology and physicochemistry in controlling trace metal uptake from solution clearly varies between species.KEY WORDS: Zinc uptake · Salinity · Osmolality · Crabs · Carcinus maenas · Eriocheir sinensis · Necora puber Resale or republication not permitted without written consent of the publisher

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We calculate the supergravity fields sourced by a D-brane with a null travelling wave from disk amplitudes in type IIB string theory compactified on T 4 ×S 1 . The amplitudes reproduce all the nontrivial features of the previously known two-charge supergravity solutions in the D-brane/momentum duality frame, providing a direct link between the microscopic bound states and their macroscopic descriptions.

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String-brane interactions provide an ideal framework to study the dynamics of the massive states of the string spectrum in a non-trivial background. We present here an analysis of tree-level amplitudes for processes in which an NS-NS string state from the leading Regge trajectory scatters from a D-brane into another state from the leading Regge trajectory, in general of a different mass, at high energies and small scattering angles. This is done by using world-sheet OPE methods and effective vertex operators. We find that this class of processes has a universal dependence on the energy of the projectile. We then compare the result for these inelastic processes with that which one would obtain from the eikonal operator in a non-trivial test of its ability to describe transitions between different string mass levels. The two are found to be in agreement.arXiv:1107.4321v2 [hep-th]