Testes asymmetry, condition and sexual selection in birds: an experimental test

The functional significance of the marked directional asymmetry in testes size observed in many bird species is obscure. Møller suggested that (i) the smaller of the two testes serves a compensatory role and increases in size (and hence reduces asymmetry) when the larger one is defective in some way, and (ii) as a consequence, the degree of directional asymmetry in testes size reflects male quality and covaries positively with the expression of secondary sexual traits.We conducted an experimental test of these two hypotheses in the zebra finch,Taeniopygia guttata. Neither hypothesis was supported. First, there was no significant relationship between the size of the left testis and relative testes asymmetry. Second, we obtained no support for the hypothesis that the degree of directional asymmetry in testes mass covaried with condition. On the contrary, directional asymmetry in testes mass was signifcantly greater in birds whose condition was experimentally reduced, compared with control birds. Moreover, we found no significant relationships between testes asymmetry and secondary sexual traits. We conclude that directional asymmetry in testes size does not reflect male condition in the zebra finch

Currency Swaps and International Real Estate Investment

This paper examines the efficacy of currency swaps as a hedging mechanism for the exchange rate risk associated with foreign investment in real estate. Earlier studies have concentrated on short-term hedging instruments such as options and forward contracts. Currency swaps are better suited for use on investments with long-term holding periods such as real estate. The findings indicate that, although hedging United States real estate investments with currency swaps suppresses most of the risk induced by currency instability, the improvements are insufficient to produce diversification gains for foreign investors in the context of mean-variance portfolio performance. Copyright American Real Estate and Urban Economics Association.

Body mass index is negatively associated with telomere length: A collaborative cross-sectional meta-analysis of 87 observational studies

Stress-related psychiatric disorders across the life spa