The elastic moduli of the two-dimensional flux-line lattice in a uniaxial superconductor are evaluated for an arbitrary orientation of vortices (i.e., of the magnetic induction) within the crystal in intermediate fields. For the flux lines in the basal a-b plane the ratio of the simple shear moduli, corresponding to displacements normal and parallel to the basal plane, is shown to equal (ms/mi)^ where ms and m\ are the masses along the c axis and the basal plane, respectively. For YBa2Cu307 this amounts to a factor exceeding 600. The uniaxial crystal symmetry defines a preferred orientation to the flux lattice and doubles the number of independent elastic constants.

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Infectious diseases can influence the life history strategy of their hosts and such influences subsequently impact the demography of infected populations, reducing viability independently of increased mortality or morbidity. Amphibians are the most threatened group of vertebrates and emerging infectious diseases play a large role in their population declines. Viruses of genus Ranavirus are responsible for one of the deadliest of these diseases. To date no work has evaluated the impact of ranaviruses on host life-history post metamorphosis or population demographic structure at the individual level. In this study, we used skeletochronology and morphology to evaluate the impact of ranaviruses on the demography of populations of European common frog (Rana temporaria) in the United Kingdom. We compared ecologically similar populations that differed only in their historical presence or absence of ranaviral disease. Our results suggest that ranaviruses are associated with shifts in the age structure of infected populations, potentially caused by increased adult mortality and associated shifts in the life history of younger age classes. Population projection models indicate that such age truncation could heighten the vulnerability of frog populations to stochastic environmental challenges. Our individual level data provide further compelling evidence that the emergence of infectious diseases can alter host demography, subsequently increasing population vulnerability to additional stressors.

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