Weight increases significantly with increased beak size, even after accounting for the correlated variation in overall size (as measured by the two skeletal variables). The beak measurements are very highly correlated with each other, so (1) it is impossible to disentangle their relationships with weight, and (2) they are redundant so that if one is in the model neither of the others explains m...

N 1938 from matings of polydactylous fowl we found newly-hatched I chicks which had an abnormally short upper beak. In some of these chicks the beak gradually became normal, while others developed a crossbeak. The latter type has been referred to in an earlier publication (LANDAUER 1938, Postscript) as probably representing a new hereditary form of cross-beak in fowl. Further studies with this ...

Lorenzo Alibardi (2010) Cornification of the beak of Rana dalmatina tadpoles suggests the presence of basic keratin-associated proteins. Zoological Studies 49(1): 51-63. An ultrastructural, immunocytochemical, and electrophoretic study on keratinocytes formation in the horny beak of tadpoles of the frog Rana dalmatina was conducted. The study showed that hard cornification in amphibians occurs ...

The hard tissues found in some invertebrate marine organisms represent intriguing paradigms for robust, lightweight materials. The present study focuses on one such tissue: that comprising the beak of the jumbo squid (Dosidicus gigas). Its main constituents are chitin fibers (15-20wt.%) and histidine- and glycine-rich proteins (40-45%). Notably absent are mineral phases, metals and halogens. De...

Compared to male secondary sexual traits, the effect of testosterone (T) on female ornaments is understudied. In particular, it is unclear whether females experience different costs of T elevation than do males and how this affects the relationship between T and ornamentation in the two sexes. I experimentally and correlationally investigated the effect of T on the color of the carotenoid-based...

Introduction The anterior ethmoidal artery (AEA) is one of the main arteries that supply both the nasal mucosa and the ethmoid sinuses. The AEA shows variability regarding its distance from adjacent structures. Several studies have developed techniques to identify the AEA. Objective This study aimed to compare the measurements from the AEA to the ethmoid bulla and to the frontal beak by using c...

Evolution by natural selection has resulted in a remarkable diversity of organism morphologies that has long fascinated scientists and served to establish the first relations among species. Despite the essential role of morphology as a phenotype of species, there is not yet a formal, mathematical scheme to quantify morphological phenotype and relate it to both the genotype and the underlying de...

Eukaryotic flagella and cilia can exhibit planar and non-planar beating, and the mechanism controlling these beating patterns is not well understood. Chlamydomonas reinhardtii flagella beat in approximately the same plane with either an asymmetric ciliary-type or symmetric flagellar-type waveform. Each B-tubule of the number 1, 5 and 6 doublets of the flagellar axoneme possesses a beak-like str...

Artificial neural networks (ANN) are used for statistical modeling of spatial events in geosciences. The advantage of this method is the ability of neural networks to represent complex interrelations and to be “able to learn” from known (spatial) events. The software advangeo® was developed to enable GIS users to apply neural network methods on raster geodata. This statistic modeling can be dis...

Natural antibodies (NAb) are important humoral components of innate immunity. As the first line of defense, NAb provide protection against infection and support adaptive immunity. An earlier study indicated that serum levels of NAb isotypes IgM and IgG at a young age were predictive for survival in non-beak-trimmed purebred laying hens during the laying period. In the present study, genetic par...