14,113 research outputs found

    Nature and origin of fluids in granulite facies metamorphism

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    The various models for the nature and origin of fluids in granulite facies metamorphism were summarized. Field and petrologic evidence exists for both fluid-absent and fluid-present deep crustal metamorphism. The South Indian granulite province is often cited as a fluid-rich example. The fluids must have been low in H2O and thus high in CO2. Deep crustal and subcrustal sources of CO2 are as yet unproven possibilities. There is much recent discussion of the possible ways in which deep crustal melts and fluids could have interacted in granulite metamorphism. Possible explanations for the characteristically low activity of H2O associated with granulite terranes were discussed. Granulites of the Adirondacks, New York, show evidence for vapor-absent conditions, and thus appear different from those of South India, for which CO2 streaming was proposed. Several features, such as the presence of high-density CO2 fluid inclusions, that may be misleading as evidence for CO2-saturated conditions during metamorphism, were discussed

    Advanced bearing study. Part 2: Bearing tests

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    Tests of ball bearings of various material combinations in liquid hydroge

    Deconstructing triplet nucleon-nucleon scattering

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    Nucleon-nucleon scattering in spin-triplet channels is analysed within an effective field theory where one-pion exchange is treated nonperturbatively. Justifying this requires the identification of an additional low-energy scale in the strength of that potential. Short-range interactions are organised according to the resulting power counting, in which the leading term is promoted to significantly lower order than in the usual perturbative counting. In each channel there is a critical momentum above which the waves probe the singular core of the tensor potential and the new counting is necessary. When the effects of one- and two-pion exchange have been removed using a distorted-wave Born approximation, the residual scattering in waves with L<=2 is well described by the first three terms in the new counting. In contrast, the scattering in waves with L>=3 is consistent with the perturbative counting, at least for energies up to 300 MeV. This pattern is in agreement with estimates of the critical momenta in these channels.Comment: 13 pages, RevTeX, 8 figures, minor clarifications adde

    Reduction of errors in vibratory gyroscopes by double modulation

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    Reduction of errors in vibratory gyroscopes by double modulatio

    Early production of the passive in two Eastern Bantu languages

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    The passive construction is acquired relatively late by children learning to speak many languages, with verbal passives not fully acquired till age 6 in English. In other languages it appears earlier, around age 3 or before. Use of passive construction in young children was examined in two Eastern Bantu languages spoken in Kenya (Kiswahili and Kigiriama), both with frequent use of passive. The passive was used productively very early (2;1) in these languages, regardless of the method used to measure productivity. In addition non-actional passives, particularly rare in English and some other European languages, were seen at these early ages. The proportion of verbs that were passive varied between individuals, both in children's speech and in the input to children. Pragmatic and grammatical features of the passive in some languages have previously been suggested to drive early passive acquisition, but these features are not found consistently in the two languages studied here. Findings suggest that the relatively high frequency of input found in these languages is the most plausible reason for early productive use of the passive

    The Strong Levinson Theorem for the Dirac Equation

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    We consider the Dirac equation in one space dimension in the presence of a symmetric potential well. We connect the scattering phase shifts at E=+m and E=-m to the number of states that have left the positive energy continuum or joined the negative energy continuum respectively as the potential is turned on from zero.Comment: Submitted to Physical Review Letter

    Accent identification by adults with aphasia

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    The UK is a diverse society where individuals regularly interact with speakers with different accents. Whilst there is a growing body of research on the impact of speaker accent on comprehension in people with aphasia, there is none which explores their ability to identify accents. This study investigated the ability of this group to identify the geographical origins of a speaker. Age-matched participants with and without aphasia listened to 120 audio recordings of five speakers each of six accents, reading aloud four sentences each. Listeners were asked to make a forced-choice decision about the geographical origin of the speaker. Adults with aphasia were significantly less accurate than control participants at identifying accents but both groups made the same pattern of errors. Adults with aphasia who are able to identify a new speaker as being from a particular place may draw on this information to help them “tune in” to the accent

    Data on Apollo 11 and 12 samples. Speculations on petrologic differentiation Final report

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    Petrologic and mineralogic studies of Apollo 11 and 12 lunar rock

    Levinson's Theorem for Non-local Interactions in Two Dimensions

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    In the light of the Sturm-Liouville theorem, the Levinson theorem for the Schr\"{o}dinger equation with both local and non-local cylindrically symmetric potentials is studied. It is proved that the two-dimensional Levinson theorem holds for the case with both local and non-local cylindrically symmetric cutoff potentials, which is not necessarily separable. In addition, the problems related to the positive-energy bound states and the physically redundant state are also discussed in this paper.Comment: Latex 11 pages, no figure, submitted to J. Phys. A Email: [email protected], [email protected]

    Levinson's theorem for the Schr\"{o}dinger equation in two dimensions

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    Levinson's theorem for the Schr\"{o}dinger equation with a cylindrically symmetric potential in two dimensions is re-established by the Sturm-Liouville theorem. The critical case, where the Schr\"{o}dinger equation has a finite zero-energy solution, is analyzed in detail. It is shown that, in comparison with Levinson's theorem in non-critical case, the half bound state for PP wave, in which the wave function for the zero-energy solution does not decay fast enough at infinity to be square integrable, will cause the phase shift of PP wave at zero energy to increase an additional π\pi.Comment: Latex 11 pages, no figure and accepted by P.R.A (in August); Email: [email protected], [email protected]
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