The origin of stiffening in cross-linked semiflexible networks

Strain stiffening of protein networks is explored by means of a finite strain analysis of a two-dimensional network model of cross-linked semiflexible filaments. The results show that stiffening is caused by non-affine network rearrangements that govern a transition from a bending dominated response at small strains to a stretching dominated response at large strains. Thermally-induced filament undulations only have a minor effect; they merely postpone the transition.Comment: 5 pages, 5 figure

Efficiency of Hedging Against Fluctuating Prices of Dairy Products

This paper investigates hedging and cross-hedging internationally traded milk derivative products with internationally traded commodities, recently launched New Zealand dairy futures, New Zealand agricultural products, and mature United States dairy market futures. The contribution of the paper is twofold. First, we show that international dairy commodities are a distinct commodities subgroup, as changes in prices of dairy products are uncorrelated with other worldwide traded commodities. Second, we show that New Zealand Stock Exchange dairy futures are an effective tool for hedging exposure to smaller size trades and may not necessarily be of large positions as required by cooperatives and multinationals

Determining the Elemental and Isotopic Composition of the preSolar Nebula from Genesis Data Analysis: The Case of Oxygen

We compare element and isotopic fractionations measured in solar wind samples collected by NASA's Genesis mission with those predicted from models incorporating both the ponderomotive force in the chromosphere and conservation of the first adiabatic invariant in the low corona. Generally good agreement is found, suggesting that these factors are consistent with the process of solar wind fractionation. Based on bulk wind measurements, we also consider in more detail the isotopic and elemental abundances of O. We find mild support for an O abundance in the range 8.75 - 8.83, with a value as low as 8.69 disfavored. A stronger conclusion must await solar wind regime specific measurements from the Genesis samples.Comment: 6 pages, accepted by Astrophysical Journal Letter