1,330 research outputs found

    Evaluative criteria for spelling

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    Thesis (Ed.M.)--Boston UniversityThe purpose of this study is to develop a set of criteria to evaluate the spelling area of an elementary school. The criteria consists of specific statements indicating desirable conditions and procedures in certain areas of the elementary school program. SUch statements should furnish a means for teachers to examine and evaluate the effectiveness of their own work. The Evaluative Criteria, an instrument by which a secondary school can be evaluated through making a self-evaluation, was developed by the Cooperative Study of Secondary-School Standards in 19~0 and revised in 1950. These criteria have been used extensively and successfully throughout the United States. Because it has been proved through use of the instrument that self-evaluation leads to improvement, it seemed pertinent to develop similar instrument by which an elementary school can be evaluated

    William Butler Yeats and the Noh, the concept of spiritual reality in At the Hawk\u27s Well and Atsumori

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    Quantum dynamics of a binary mixture of BECs in a double well potential: an Holstein-Primakoff approach

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    We study the quantum dynamics of a binary mixture of Bose-Einstein condensates (BEC) in a double-well potential starting from a two-mode Bose-Hubbard Hamiltonian. Focussing on the regime where the number of atoms is very large, a mapping onto a SU(2) spin problem together with a Holstein-Primakoff transformation is performed. The quantum evolution of the number difference of bosons between the two wells is investigated for different initial conditions, which range from the case of a small imbalance between the two wells to a coherent spin state. The results show an instability towards a phase-separation above a critical positive value of the interspecies interaction while the system evolves towards a coherent tunneling regime for negative interspecies interactions. A comparison with a semiclassical approach is discussed together with some implications on the experimental realization of phase separation with cold atoms.Comment: 12 pages, 7 figures, accepted for publication in J. Phys.

    Quantum Bose Josephson Junction with binary mixtures of BECs

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    We study the quantum behaviour of a binary mixture of Bose-Einstein condensates (BEC) in a double-well potential starting from a two-mode Bose-Hubbard Hamiltonian. We focus on the small tunneling amplitude regime and apply perturbation theory up to second order. Analytical expressions for the energy eigenvalues and eigenstates are obtained. Then the quantum evolution of the number difference of bosons between the two potential wells is fully investigated for two different initial conditions: completely localized states and coherent spin states. In the first case both the short and the long time dynamics is studied and a rich behaviour is found, ranging from small amplitude oscillations and collapses and revivals to coherent tunneling. In the second case the short-time scale evolution of number difference is determined and a more irregular dynamics is evidenced. Finally, the formation of Schroedinger cat states is considered and shown to affect the momentum distribution.Comment: 14 pages, 4 figure

    Assessing molecular outflows and turbulence in the protostellar cluster Serpens South

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    Molecular outflows driven by protostellar cluster members likely impact their surroundings and contribute to turbulence, affecting subsequent star formation. The very young Serpens South cluster consists of a particularly high density and fraction of protostars, yielding a relevant case study for protostellar outflows and their impact on the cluster environment. We combined CO J=1−0J=1-0 observations of this region using the Combined Array for Research in Millimeter-wave Astronomy (CARMA) and the Institut de Radioastronomie Millim\'{e}trique (IRAM) 30 m single dish telescope. The combined map allows us to probe CO outflows within the central, most active region at size scales of 0.01 pc to 0.8 pc. We account for effects of line opacity and excitation temperature variations by incorporating 12^{12}CO and 13^{13}CO data for the J=1−0J=1-0 and J=3−2J=3-2 transitions (using Atacama Pathfinder Experiment and Caltech Submillimeter Observatory observations for the higher CO transitions), and we calculate mass, momentum, and energy of the molecular outflows in this region. The outflow mass loss rate, force, and luminosity, compared with diagnostics of turbulence and gravity, suggest that outflows drive a sufficient amount of energy to sustain turbulence, but not enough energy to substantially counter the gravitational potential energy and disrupt the clump. Further, we compare Serpens South with the slightly more evolved cluster NGC 1333, and we propose an empirical scenario for outflow-cluster interaction at different evolutionary stages.Comment: 26 pages, 15 figures, accepted for publication in the Astrophysical Journa

    Empirical analysis of the impact of globalization on labor force utilization: Evidence from Nigeria

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    In this study, the impact of globalization on labor force utilization, proxied as employment, in Nigeria was addressed with a view to assessing the extent to which globalization has influenced the structure of development in Nigeria. To achieve this, Augmented Dickey Fuller (ADF) test, and cointegration test were performed to investigate the unit root problem and the long run relationship among variables respectively; also an Error Correction Methodology was applied with a view to capturing both the short run and long run dynamic adjustments in employment model. The findings that emerged from the analysis showed that globalization practice could generate negative impact on employment in both short- and long run periods suggesting that if globalization continues as being practiced, globalization could further worsen the extant decrepit state of unemployment in Nigeria other things being equal. It is therefore recommended that government should confront the imminent unavoidable negative effects of globalization with a well –designed policy mix

    Quantum phase excitations in Ginzburg-Landau superconductors

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    We give a straightforward generalization of the Ginzburg-Landau theory for superconductors where the scalar phase field is replaced by an antisymmetric Kalb-Ramond field. We predict that at very low temperatures, where quantum phase effects are expected to play a significant role, the presence of vortices destroys superconductivity.Comment: revtex, 4 pages, no figure

    Fluorescent visualization of a spreading surfactant

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    The spreading of surfactants on thin films is an industrially and medically important phenomenon, but the dynamics are highly nonlinear and visualization of the surfactant dynamics has been a long-standing experimental challenge. We perform the first quantitative, spatiotemporally-resolved measurements of the spreading of an insoluble surfactant on a thin fluid layer. During the spreading process, we directly observe both the radial height profile of the spreading droplet and the spatial distribution of the fluorescently-tagged surfactant. We find that the leading edge of spreading circular layer of surfactant forms a Marangoni ridge in the underlying fluid, with a trough trailing the ridge as expected. However, several novel features are observed using the fluorescence technique, including a peak in the surfactant concentration which trails the leading edge, and a flat, monolayer-scale spreading film which differs from concentration profiles predicted by current models. Both the Marangoni ridge and surfactant leading edge can be described to spread as R∝tήR \propto t^{\delta}. We find spreading exponents, ήH≈0.30\delta_H \approx 0.30 and ήΓ≈0.22\delta_\Gamma \approx 0.22 for the ridge peak and surfactant leading edge, respectively, which are in good agreement with theoretical predictions of ή=1/4\delta = 1/4. In addition, we observe that the surfactant leading edge initially leads the peak of the Marangoni ridge, with the peak later catching up to the leading edge

    Point-like topological defects in bilayer quantum Hall systems

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    Following a suggestion given in Phys. Lett. B 571 (2003) 250, we show how a bilayer Quantum Hall system at fillings nu =m/pm+2 can exhibit a point-like topological defect in its edge state structure. Indeed our CFT theory for such a system, the Twisted Model (TM), gives rise in a natural way to such a feature in the twisted sector. Our results are in agreement with recent experimental findings (cond-mat/0503478) which evidence the presence of a topological defect in the bilayer system.Comment: 9 pages, 3 figure

    Testing carbon farming opportunities for salinity management

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    An emerging prospect for farm revenue from revegetation of saline and other lands that are marginal or non-productive for agriculture is the sale of carbon credits. Australian Government schemes for carbon credits include the Carbon Farming Initiative (CFI) and the proposed Emissions Reduction Fund (ERF) Therefore, this study aimed to assess the potential for woody vegetation (trees and shrubs) established on and around salt-affected lands in the Northern Agricultural Region (NAR) to remove carbon dioxide from the atmosphere and store (sequester) the carbon in new growth. Revegetation plantings on six farms were selected for the study after the landowners expressed interest in participating in the study. Criteria for selection included: minimum of 5 ha planted on and around salt-affected land; a variety of native trees and shrub species planted; and that the plantings must be at least 10 years old. Across the six farms a total of nine sites were selected for the study. The estimates of carbon stocks in species and sites were projected forwards and backwards from the measurement ages (11 - 22 years)to age 15 years to \u27age standardise\u27 the results and facilitate comparison between species and sites. This was done using the national carbon accounting model, FullCAM
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