The hen's egg: Evidence on the mechanism relating shell strength to loading rate

1. The decrease in strength of an egg shell which is known to accompany an increase in the period of time over which a load is applied might come about by either of two mechanisms: a decrease in the strength of the material constituting the strong, outer layer of the mineral shell, or a decrease in the thickness of this layer brought about by deepening of the crevices that are normally present between adjacent crystal columns in the weak, inner layer of the shell.

2. Experiments designed to discriminate between these mechanisms are described: the results indicate the second mechanism.

3. This mechanism offers explanations for various other shell phenomena, including delayed fracture under a static, cyclical or recurrent load.

4. The main implication for the poultry industry is that any external insult to a shell is likely to weaken it by doing damage that is local, internal, irreparable and cumulative, even though it may be invisible from the outside.     

Bovine abortion associated with mixed Movar 33/63 type herpesvirus and bovine viral diarrhea virus infection.

A herpesvirus and cytopathogenic bovine viral diarrhea virus were isolated from a bovine fetus aborted in the 6th month of gestation. The herpesvirus was serologically indistinguishable from bovine herpesviruses DN-599 and Movar 33/63.     

Scanning electron microscopic studies on males of trichinella species

Ultrastructure of the cuticle and pseudobursa of adult males of four species of Trichinella has been studied by SEM. T. nativa differs markedly from T. spiralis, T. nelsoni and Trichinella sp. in the form of the pseudobursa. Trichinella sp. differs only slightly from T. spiralis and T. nelsoni. The ultrastructure of the cuticle revealed no characters suitable for the differentiation of the taxons under study.     

Superheavy elements: a crossroads

The failure to synthesize superheavy elements by using complete fusion reactions is most likely understandable in terms of the low survival probabilities of the superheavy precursors formed in these reactions or (in some cases) the failure to achieve complete fusion. Further attempts to synthesize these elements by using complete fusion or deep inelastic transfer reactions, or both, are discussed in light of these results.     

Book reviews

Research and Development in Relation to Farm Animal Welfare, contributions by B. A. Baldwin, J. R. Bareham, I. J. H. Duncan, R. Ewbank, D. C. Hardwick and K. Vestergaard, Animal Management, 11, Series Edited by D. W. Fölsch. Birkhauser Verlag, Basel, 1981. ISBN‐3–7643–1241–6.

First European Symposium on Poultry Welfare. Edited by L. Yding S0RENSEN. Published by the Danish Branch of World's Poultry Science Association. 1981. 238pp. D.Kr.90. ISBN 87–88162–00–1.