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Laying hens develop a type of osteoporosis that arises from a loss of structural bone, resulting in high incidence of fractures. In this study, a comparison of bone material properties was made for lines of hens created by divergent selection to have high and low bone strength and housed in either individual cages, with restricted mobility, or in an aviary system, with opportunity for increased mobility. Improvement of bone biomechanics in the high line hens and in aviary housing was mainly due to increased bone mass, thicker cortical bone and more medullary bone. However, bone material properties such as cortical and medullary bone mineral composition and crystallinity as well as collagen maturity did not differ between lines. However, bone material properties of birds from the different type of housing were markedly different. The cortical bone in aviary birds had a lower degree of mineralization and bone mineral was less mature and less organized than in caged birds. These differences can be explained by increased bone turnover rates due to the higher physical activity of aviary birds that stimulates bone formation and bone remodeling. Multivariate statistical analyses shows that both cortical and medullary bone contribute to breaking strengthThe cortical thickness was the single most important contributor while its degree of mineralization and porosity had a smaller contribution. Bone properties had poorer correlations with mechanical properties in cage birds than in aviary birds presumably due to the greater number of structural defects of cortical bone in cage birds.

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Guerra, Á., Rodríguez-Navarro, A. B., González, Á. F., Romanek, C. S., Álvarez-Lloret, P., and Pierce, G. J. 2010. Life-history traits of the giant squid Architeuthis dux revealed from stable isotope signatures recorded in beaks. – ICES Journal of Marine Science, 67: 1425–1431. Carbon and nitrogen isotope profiles constructed from the upper beaks of four giant squid Architeuthis dux from the Bay of Biscay and Namibian waters provided a time-integrated record of their diet. Values of δ15N ranged from 5.5 to 13.4‰ and of δ13C from −14.4 to −17.8‰. Nitrogen isotope profiles differed significantly in shape among the four animals analysed, but δ15N increased along each profile, with lowest values around the rostral tip. The difference between the lowest and the highest δ15N values was ∼5.8‰, slightly less than a two-level difference between the trophic position of small and large A. dux. The increase in δ13C values was not as pronounced as for the δ15N profiles, but the changes suggest an ontogenetic shift in diet early in life from smaller prey of relatively low trophic status to larger prey of higher status. Fluctuations in δ13C values observed near the rostral tip may be associated with a greater intrinsic variability in the carbon isotope composition of relatively small prey, and/or transient migratory behaviour early in life. The relative stability of the δ13C profiles over the remainder of their lifespan is consistent with the hypothesis that adult giant squid inhabit relatively small, well-defined, and productive areas, where food resources have a constant carbon isotope composition.

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Crystal sizes can be calculated from peak intensities of spotty diffraction rings produced by a polycrystalline sample. Such patterns are collected using a small X‐ray beam and an area detector. Peak intensities can be automatically measured using specially designed software. Crystal sizes can be determined from peak intensities after calibration using samples of the same material whose sizes are already known. This technique is independent of the aggregation state of the material. Also, crystal sizes of different mineral phases present in a sample can be analyzed independently. The present paper analyzes the potential of this methodology as applied to crystal size characterization of crystalline powder materials. Graded SiC and α‐Al2O3 abrasive powders were selected as test material for this study. A high correlation was found between parameters determined by X‐ray diffraction and crystal size determined by means of optical microscopy and laser diffraction. The crystal sizes determined ranges from 3 to 80 μm, a much larger range than that obtained by conventional X‐ray line‐broadening analyses. Additionally, upper and lower size ranges of applicability of this technique can be extended further by using different collimator diameters. The estimated error in crystal size measurements was within 5%.

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