3,562 research outputs found

    Civic Service Worldwide: Defining a Field, Building a Knowledge Base.

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    In this article, the authors summarize results of a global assessment of civic service. Searching by country and using information from organizational memberships, publications, and the Internet, 210 civic service programs were identified in 57 countries

    Galaxy destruction and diffuse light in clusters

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    Deep images of the Centaurus and Coma clusters reveal two spectacular arcs of diffuse light that stretch for over 100 kpc, yet are just a few kpc wide. At a surface brightness of m_b \sim 27-28th arcsec^-2, the Centaurus arc is the most striking example known of structure in the diffuse light component of a rich galaxy cluster. We use numerical simulations to show that the Centaurus feature can be reproduced by the tidal debris of a spiral galaxy that has been tidally disrupted by the gravitational potential of NGC 4709. The surface brightness and narrow dimensions of the diffuse light suggest that the disk was co-rotating with its orbital path past pericentre. Features this prominent in clusters will be relatively rare, although at fainter surface brightness levels the diffuse light will reveal a wealth of structure. Deeper imaging surveys may be able to trace this feature for several times its presently observed extent and somewhere along the tidal debris, a fraction of the original stellar component of the disk will remain bound, but transformed into a faint spheroidal galaxy. It should be possible to confirm the galactic origin of the Centaurus arc by observing planetary nebulae along its length with redshifts close to that of NGC 4709.Comment: Replaced with version accepted by MNRAS (Dec. 1999): Added missing reference (to pg. 4 & reference list). Section 3 shortened; removed three figures. Now 8 pages long, with 8 figures. Low resolution images included, high resolution version available at http://star-www.dur.ac.uk:80/~calcaneo/cenarc.htm

    Carlos Ichter, Alan Moore, and Kale Magness in a Joint Junior Voice Recital

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    This is the program for the joint junior voice recital of baritone Carlos Ichter, baritone Alan Moore, and baritone Kale Magness. Pianist Linda Tapson accompanied Ichter; pianist Lisa Nevin accompanied Moore; and pianist Susan White accompanied Magness. The recital took place on March 26, 1982, in the Mabee Fine Arts Center Recital Hall

    Civic Service Worldwide: Social Development Goals and Partnerships

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    Civic service is a long-term, intensive form of volunteering. This article reports on a global assessment of civic service, which identified 210 programs in 57 countries. Program goals and administrative partnerships suggest that civic service is a social development intervention. For civic service to achieve its potential, research is recommended regarding server inclusivity, goal accomplishment, and the nature and effect of partnerships

    Influence of anisotropy on velocity and age distribution at Scharffenbergbotnen blue ice area

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    We use a full-Stokes thermo-mechanically coupled ice-flow model to study the dynamics of the glacier inside Scharffenbergbotnen valley, Dronning Maud Land, Antarctica. The domain encompasses a high accumulation rate region and, downstream a sublimation-dominated bare ice ablation area. The ablation ice area is notable for having old ice at its surface since the vertical velocity is upwards, and horizontal velocities are almost stagnant there. We compare the model simulation with field observations of velocities and the age distribution of the surface ice. A satisfactory match with simulations using an isotropic flow law was not found because of too high horizontal velocities and too slow vertical ones. However, the existence of a pronounced ice fabric may explain the present day surface velocity distribution in the inner Scharffenbergbotnen blue ice area. Near absence of data on the temporal evolution of Scharffenbergbotnen since the Late Glacial Maximum necessitates exploration of the impact of anisotropy using prescribed ice fabrics: isotropic, single maximum, and linear variation with depth, in both two-dimensional and three dimensional flow models. The realistic velocity field simulated with a non-collinear orthotropic flow law, however produced surface ages in significant disagreement with the few reliable age measurements and suggests that the age field is not in a steady state and that the present distribution is a result of a flow reorganization at about 15 000 yr BP. In order to fully understand the surface age distribution a transient simulation starting from the Late Glacial Maximum including the correct initial conditions for geometry, age, fabric and temperature distribution would be needed. It is the first time that the importance of anisotropy has been demonstrated in the ice dynamics of a blue ice area. This is useful to understand ice flow in order to better interpret archives of ancient ice for paleoclimate research

    Chaotic Coupling Constants

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    We examine some novel physical consequences of the general structure of moduli spaces of string vacua. These include (1) finiteness of the volume of the moduli space and (2) chaotic motion of the moduli in the early universe. To fix ideas we examine in detail the example of the (conjectural) dilaton-axion ``SS-duality'' of four-dimensional string compactifications. The facts (1) and (2) together might help to solve some problems with the standard scenarios for supersymmetry breaking and vacuum selection in string theory.Comment: 18 pages (4 figs), YCTP-P2-94, RU-94-2

    Youth Volunteerism and Civic Service in Latin America and the Caribbean: A Potential Strategy for Social and Economic Development

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    Youth Volunteerism and Civic Service in Latin America and the Caribbean: A Potential Strategy for Social and Economic Developmen

    Two Higgs doublet dynamics at the electroweak phase transition: a non-perturbative study

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    Using a three-dimensional (3d) effective field theory and non-perturbative lattice simulations, we study the MSSM electroweak phase transition with two dynamical Higgs doublets. We first carry out a general analysis of spontaneous CP violation in 3d two Higgs doublet models, finding that this part of the parameter space is well separated from that corresponding to the physical MSSM. We then choose physical parameter values with explicit CP violation and a light right-handed stop, and determine the strength of the phase transition. We find a transition somewhat stronger than in 2-loop perturbation theory, leading to the conclusion that from the point of view of the non-equilibrium constraint, MSSM electroweak baryogenesis can be allowed even for a Higgs mass mH \approx 115 GeV. We also find that small values of the mass parameter mA (\lsim 120 GeV), which would relax the experimental constraint on mH, do not weaken the transition noticeably for a light enough stop. Finally we determine the properties of the phase boundary.Comment: 56 pages, 16 figures; small clarifications added, concerning e.g. Higgs mass bounds; to appear in NP

    The Knowledge Base on Civic Service: Status and Directions

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    The Knowledge Base on Civic Service: Status and Direction
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