منابع مشابه
Crested Products of Association Schemes
In this paper, we define a new type of product of association schemes (and of the related objects, permutation groups and orthogonal block structures), which generalizes the direct and wreath products (which are referred to as “crossing” and “nesting” in the statistical literature.) Given two association schemes Qr for r = 1, 2, each having an inherent partition Fr (that is, a partition whose e...
متن کاملBrain alterations in crested versus non-crested breeds of domestic ducks (Anas platyrhynchos f.d.).
A comparison of brain size and brain composition was made between two uncrested duck breeds and Crested Ducks (CR) and between CR individuals that do possess crests and those that do not have the crest. Domestic ducks of the breed CR have allometrically larger brains than uncrested duck breeds. The crest inserts on a cushion of fat and connective tissue that is partly nourished by brain vessels...
متن کاملDomestic pigeons
Figure 1. Diversity among breeds of domestic pigeons (Columba livia). Variation among pigeon breeds is often of the magnitude observed among different species of birds, including beak size extremes of the (A) African owl and (B) Scandaroon; (C) the head crest of the Old German owl and (D) hood of the Jacobin; (E) supernumerary and elevated tail feathers of the fantail; and (F) scales versus (G)...
متن کاملCrested Products of Markov Chains
In this work we define two kinds of crested product for reversible Markov chains, which naturally appear as a generalization of the case of crossed and nested product, as in association schemes theory, even if we do a construction that seems to be more general and simple. Although the crossed and nested product are inspired by the study of Gelfand pairs associated with the direct and the wreath...
متن کاملEchoic memory in pigeons.
It is unknown whether birds are able to retain the memory of purely sensory auditory information such as white noise over an extended period of time. In a Pavlovian heart rate conditioning paradigm, four pigeons were trained to associate a mild electric shock with periodic random waveforms, and no shock with aperiodic noise. Periodic waveform detection requires echoic memory, i.e., the online r...
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ژورنال
عنوان ژورنال: Emu - Austral Ornithology
سال: 1917
ISSN: 0158-4197,1448-5540
DOI: 10.1071/mu916189a