6,162 research outputs found

    Possible multiple evolution of indirect telencephalo-cerebellar pathways in teleosts: studies in Carassius auratus and Pantodon buchholzi

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    Among vertebrates, telencephalo-pontine systems exist only in birds and mammals. However, three nuclei in the diencephalon and mesencephalon of teleost fishes have been indicated — analogous to the pons — to represent relay stations between telencephalon and cerebellum. Since two of these nuclei (dorsal preglomerular nucleus, dorsal tegmental nucleus) have only been described in the highly derived, electrosensory mormyrids, we investigated telencephalic connections in two nonelectrosensory teleosts, the goldfish Carassius auratus and the freshwater butterflyfish Pantodon buchholzi, and cerebellar connections only in the latter species, since for C. auratus these connections are already established. Horseradish peroxidase tracing reveals that C. auratus has a dorsal tegmental nucleus and a paracommissural nucleus both of which are telencephalo-recipient and project to the cerebellum, and that P. buchholzi has a dorsal preglomerular nucleus with such connections. These results extend our knowlegde of the distribution and, therefore, the phylogeny of telencephalo-cerebellar systems in teleosts. Similar to tetrapods, teleosts appear to have developed telencephalo-cerebellar systems several times independently

    The valvula cerebelli of the spiny eel, Macrognathus aculeatus, receives primary lateral-line afferents from the rostrum of the upper jaw

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    In the spiny eel, Macrognathus aculeatus, anterodorsal and (to a lesser degree) anteroventral lateralline nerves project massively to the granular layer of the valvula cerebelli, throughout its rostrocaudal extent. The posterior lateral-line nerve terminates in the corpus cerebelli. Thus, valvula and corpus cerebelli are supplied with mechanosensory input of different peripheral origins. An analysis of the taxonomic distribution of experimentally determined primary lateral-line input to the three parts of the teleostean cerebellum reveals that the eminentia granularis always receives such input, and that the corpus cerebelli is the recipient of primary lateral-line input in many teleosts. The valvula, however, receives primary lateral-line afferents in only two examined species. In M. aculeatus, the massive lateral-line input to the valvula probably originates in mechanoreceptors located in the elongated rostrum of the upper jaw, a characteristic feature of mastacembeloid fishes. This projection to the valvula may therefore represent a unique specialization that arose with the evolution of the peculiar rostrum

    Ecology of religion: a hermeneutical model

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    We have to investigate the function of religion, the nature of the environment, and the nature of the human being. We have to ask: what is the nature of the relationship which connects people to their world? The aim of this paper is to present the outline of a new hermeneutical model in ecology of religion. Here the term "ecology of religion" serves as an umbrella to unify different methodological tools which are needed. As the term ecology implies, what is at issue is the impact of the environment on religion investigated through the interrelation between living organisms and their environment. From the fact that the subfield is defined as contextual research, it follows that the environment is principally a non-religious context. The orientation for ecology of religion, as represented here, is the investigation of the direct interrelation of the human being, actor in all cultural processes, with the natural environment. If it were our intention to reduce human nature to a biological organism, then we could place our approach in the field of biology. But, because it is our intention to show that the human being by nature is essentially one that lives a religion and is enabled to do so through cognitive processes, it is cognitive psychology that offers the orientation for our research

    Cosmic Ray Nuclei (CRN) detector investigation

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    The Cosmic Ray Nuclei (CRN) detector was designed to measure elemental composition and energy spectra of cosmic radiation nuclei ranging from lithium to iron. CRN was flown as part of Spacelab 2 in 1985, and consisted of three basic components: a gas Cerenkov counter, a transition radiation detector, and plastic scintillators. The results of the experiment indicate that the relative abundance of elements in this range, traveling at near relativistic velocities, is similar to those reported at lower energy
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