Deconvolving mutational patterns of poliovirus outbreaks reveals its intrinsic fitness landscape.

Vaccination has essentially eradicated poliovirus. Yet, its mutation rate is higher than that of viruses like HIV, for which no effective vaccine exists. To investigate this, we infer a fitness model for the poliovirus viral protein 1 (vp1), which successfully predicts in vitro fitness measurements. This is achieved by first developing a probabilistic model for the prevalence of vp1 sequences that enables us to isolate and remove data that are subject to strong vaccine-derived biases. The intrinsic fitness constraints derived for vp1, a capsid protein subject to antibody responses, are compared with those of analogous HIV proteins. We find that vp1 evolution is subject to tighter constraints, limiting its ability to evade vaccine-induced immune responses. Our analysis also indicates that circulating poliovirus strains in unimmunized populations serve as a reservoir that can seed outbreaks in spatio-temporally localized sub-optimally immunized populations

Optimal strain gage location for determination of mode I stress intensity factor for orthotropic laminates using a single strain gage

The present work discusses a robust method developed for determination of mode I stress intensity factor (KI) of orthotropic laminates using a single strain gage and based on a three parameter strain series representation ahead of the crack tip. Appropriate radial location of the strain gage ahead of the crack tip is important in the sense that strain gages placed either very near or very far from the crack tip might lead to inaccuracies in the estimated SIFs due to 3D effects near the crack tip or inaccurate strain field representation at farther distances. The theoretical formulation has been presented for determination of angular location, orientation and the upper bound on the radial location (rmax) for pasting the strain gage which could be subsequently used for accurate determination of KI. Numerical simulations have been presented considering edge cracked [902/0]10S carbon-epoxy orthotropic laminates to illustrate the determination of rmax and KI of such laminates

Dynamical Correlations in a Half-Filled Landau Level

We formulate a self-consistent field theory for the Chern-Simons fermions to study the dynamical response function of the quantum Hall system at $\nu=1/2$. Our scheme includes the effect of correlations beyond the random-phase approximation (RPA) employed to this date for this system. The resulting zero-frequency density response function vanishes as the square of the wave vector in the long-wavelength limit. The longitudinal conductivity calculated in this scheme shows linear dependence on the wave vector, like the experimentals results and the RPA, but the absolute values are higher than the experimental results.Comment: 4 pages, revtex, 3 figures included. Corrected typo