14,471 research outputs found

    Structures in granitic bathyliths and associated foldbelts in relation to mineral resources

    Get PDF
    There are no author-identified significant results in this report

    Triple-Pomeron Matrix Model for Dispersive Corrections to Nucleon-Nucleus Total Cross Section

    Full text link
    Dispersive corrections to the total cross section for high-energy scattering from a heavy nucleus are calculated using a matrix model, based on the triple-Pomeron behavior of diffractive scattering from a single nucleon, for the cross section operator connecting different states of the projectile nucleon . Energy-dependent effects due to the decrease in longitudinal momentum transfers and the opening of more channels with increasing energy are included. The three leading terms in an expansion in the number of inelastic transitions are evaluated and compared to exact results for the model in the uniform nuclear density approximation for the the scattering of nucleons from Pb^{208} for laboratory momenta ranging from 50 to 200 GeV/c.Comment: 16 pages, 2 figures, RevTex

    Electron paramagnetic resonance studies of slowly tumbling vanadyl spin probes in nematic liquid crystals

    Get PDF
    An analysis of EPR line shapes by the method of Polnaszek, Bruno, and Freed is made for slowly tumbling vanadyl spin probes in viscous nematic liquid crystals. The use of typical vanadyl complexes as spin probes for nematic liquid crystals is shown to simplify the theoretical analysis and the subsequent interpretation. Rotational correlation times tau and orientational ordering parameters S sub Z where slow tumbling effects are expected to be observed in vanadyl EPR spectra are indicated in a plot. Analysis of the inertial effects on the probe reorientation, which are induced by slowly fluctuating torque components of the local solvent structure, yield quantitative values for tau and S sub Z. The weakly ordered probe VOAA is in the slow tumbling region and displays these inertial effects throughout the nematic range of BEPC and Phase V. VOAA exhibits different reorientation behavior near the isotropic-nematic transition temperature than that displayed far below this transition temperature

    Development and evaluation of an intervention to improve further education students' understanding of higher education assessment criteria: three studies

    Get PDF
    Three studies about helping Further Education students prepare for study at universityThis paper reports three studies about preparing Further Education (FE) students for the transition to Higher Education (HE) by improving their understanding of HE assessment criteria. In study 1, students and tutors in both FE and HE were interviewed for a qualitative analysis of their understandings and expectations about assessment criteria. In study 2, students in FE and HE completed questionnaires measuring self-rated understanding and ability about assessment criteria, and beliefs about essay writing. Studies 1 and 2 both showed that FE students were more confident than HE students about their understanding and ability in relation to assessment criteria, but FE studentsā€™ understandings suggested more surface approaches to learning and more naĆÆve epistemological beliefs. In study 3, a workshop intervention to improve FE studentsā€™ understandings of HE assessment criteria was evaluated in a comparative longitudinal trial. The intervention reduced FE studentsā€™ self-rated understanding and ability, and promoted more sophisticated beliefs about essay writing, by comparison with students who received standard tuition. We concluded that interventions to develop more realistic understandings of what is required in academic writing could be used to prepare FE students more effectively for the transition to HE

    Epicurus\u27 Conception of the Psyche

    Get PDF
    In this paper I try to establish the following differences between Epicurean and Lucretian psyches: 1. For Lucretius, the psyche is composed of particles of air, breath, heat, and a fourth unnamed constituent. Epicurus suggests that the psyche is composed of a single kind of atom, and that it in some way resembles heat and in some way resembles breath. 2. For Epicurus, breath and heat are properties of compounds, not kinds of atoms or kinds of compound entities. Lucretius apparently takes the opposite position. 3. For Lucretius, the components of the psyche seem to be entities larger than atoms

    Comparison of synthetic membranes in the development of an in vitro feeding system for Dermanyssus gallinae

    Get PDF
    Although artificial feeding models for the poultry red mite (Dermanyssus gallinae) most frequently use biological membranes consisting of day-old chick skin, there are ethical considerations associated with the use of skin. The few studies reported in the literature that have investigated the use of synthetic membranes to feed D. gallinae in vitro have reported limited success. The current study describes an investigation into the use of synthetic membranes made from either NescofilmĀ® or rayon and silicone, used either alone or in combination with different feather or skin extracts, as well as the use of capillary tubes. In all, 12 different treatments were used, and the feeding rate of D. gallinae was compared to that of day-old chick skin. Allowing mites to feed on a membrane consisting of Nescofilm with a skin extract resulted in the highest proportion of mites feeding (32.3%), which was not significantly different to the feeding rate of mites on day-old chick skin (38.8%). This study confirms that synthetic membranes can be used to feed D. gallinae artificially. Further optimization of the membrane and mite storage conditions is still necessary, but the study demonstrates a proof of concept

    Genesis Mission Bulk Metallic Glass Solar Wind Collector: Characterization of Return Samples Available for Re-Allocation

    Get PDF
    The Genesis mission collected solar wind atoms for 28 months with a variety of collectors mounted on a spacecraft. A total of fifteen pure materials were selected as collectors based on engineering and science requirements. One of the materials was the bulk metallic glass (BMG). It was intended for collecting noble gases and solar energetic particles (SEP). This material is an amorphous metal which was custom made by C.C. Hays at the California Institute of Technology. The final glass composition is Zr58.5Nb2.8Cu15.6Ni12.8Al10.3 (in atom percent). The BMG was located on top of the wafer array mechanism and was exposed for the entire time the science canister was open (~28 months). Fortunately, the BMG did not suffer any serious damage and was intact after the Genesis canisters hard-landing into the Utah desert (Fig. 1)
    • ā€¦
    corecore