712 research outputs found

    REAL QUADRATIC NUMBER FIELDS WITH LARGE FUNDAMENTAL UNITS

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    There are many works on the determination or the estimation of the fundamental unit £ and the ideal class number h of real quadratic number fields F ([1], [3], [6] and [10], for example). The £'s which are treated in them have small orders of absolute value in comparison to their discriminants Z), that is

    Crystal Growth of Bi2_{2}Sr2_{2}CaCu2_{2}O8+δ_{8+{\delta}} Whiskers from Pulverized Amorphous Precursors

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    High-transition temperature superconducting whiskers of Bi2_{2}Sr2_{2}CaCu2_{2}O8+δ_{8+{\delta}} were successfully grown from pulverized amorphous precursors. The obtained whiskers revealed a typical composition and diffraction patterns of a superconducting Bi-2212 phase. The whiskers from tiny precursors exhibit a spiral feature, suggesting a contribution from the growth mechanism of both vapor-liquid-solid and compressive stress models. The proposed method provides longer whiskers against the growth period, compared with that from conventional root-growth method

    Medial prefrontal cortex and anterior cingulate cortex in the generation of alpha activity induced by transcendental meditation: a magnetoencephalographic study.

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    Previous EEG studies have shown that transcendental meditation (TM) increases frontal and central alpha activity. The present study was aimed at identifying the source of this alpha activity using magnetoencephalography (MEG) and electroencephalography (EEG) simultaneously on eight TM practitioners before, during, and after TM. The magnetic field potentials corresponding to TM-induced alpha activities on EEG recordings were extracted, and we attempted to localize the dipole sources using the multiple signal classification (MUSIC) algorithm, equivalent current dipole source analysis, and the multiple spatio-temporal dipole model. Since the dipoles were mapped to both the medial prefrontal cortex (mPFC) and anterior cingulate cortex (ACC), it is suggested that the mPFC and ACC play an important role in brain activity induced by TM.</p
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