3,489 research outputs found

    Policy Formulation and Implementation on Participatory Budgeting in Seoul, South Korea

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    This research analyzes the policy formulation and implementation of participatory budgeting in Seoul by using qualitative methods focusing on document research. The target time for this research is from 2010 until May 2012 when the Seoul government enacted the PB regulation for policy formulation, and from 2012 until 2016 for policy implementation. The results of the research show that Seoul government had already faced many demands for the implementation of PB before the regulation on PB was enacted. These demands are the result of two flows, that is, a political flow that regards citizen participation in the process of public policy as important and the worsening financial condition of the local government. In this situation, the change of Seoul mayor in 2011 has led the Seoul government to start policy formulation for PB. In the process of making the regulations, the CSOs that already studied a lot about PB also participated in this process. So, Seoul government has made regulation on PB with high level of citizen participation. After regulation on PB was enacted, during the implementation of PB, Seoul government seeks to increase the level of citizen participation by enhancing its representativeness and expertise. For example, Seoul government randomly select most of the PB committee members through open recruitment for representatives, make compulsory lessons in budgets school for expertise, and disclose all information and provide more opportunities for participation such as e-voting to increase the number of participants. As a result, the number of e-voting participants reached about 1% among the total population of Seoul

    X-ray and EUV Observations of Simultaneous Short and Long Period Oscillations in Hot Coronal Arcade Loops

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    We report decaying quasi-periodic intensity oscillations in the X-ray (6-12 keV) and extreme ultraviolet (EUV) channels (131, 94, 1600, 304 \AA) observed by the Fermi GBM (Gamma-ray Burst Monitor) and SDO/AIA, respectively, during a C-class flare. The estimated period of oscillation and decay time in the X-ray channel (6-12 keV) was about 202 s and 154 s, respectively. A similar oscillation period was detected at the footpoint of the arcade loops in the AIA 1600 and 304 \AA channels. Simultaneously, AIA hot channels (94 and 131 \AA) reveal propagating EUV disturbances bouncing back and forth between the footpoints of the arcade loops. The period of the oscillation and decay time were about 409 s and 1121 s, respectively. The characteristic phase speed of the wave is about 560 km/s for about 115 Mm loop length, which is roughly consistent with the sound speed at the temperature about 10-16 MK (480-608 km/s). These EUV oscillations are consistent with the SOHO/SUMER Doppler-shift oscillations interpreted as the global standing slow magnetoacoustic wave excited by a flare. The flare occurred at one of the footpoints of the arcade loops, where the magnetic topology was a 3D fan-spine with a null-point. Repetitive reconnection at this footpoint could cause the periodic acceleration of non-thermal electrons that propagated to the opposite footpoint along the arcade and precipitating there, causing the observed 202-s periodicity. Other possible interpretations, e.g. the second harmonics of the slow mode are also discussed.Comment: ApJ (in press), 13 pages, 6 figure

    Multiwavelength Observations of a Flux Rope Formation by Series of Magnetic Reconnection in the Chromosphere

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    Using high-resolution observations from the 1.6 m New Solar Telescope (NST) operating at the Big Bear Solar Observatory (BBSO), we report direct evidence of merging/reconnection of cool Hα\alpha loops in the chromosphere during two homologous flares (B- and C-class) caused by a shear motion at the footpoint of two loops. The reconnection between these loops caused the formation of an unstable flux rope which showed counterclockwise rotation. The flux rope could not reach the height of torus instability and failed to form a coronal mass ejection. The HMI magnetograms revealed rotation of the negative/positive (N1/P2) polarity sunspots in the opposite directions, which increased the right and left-handed twist in the magnetic structures rooted at N1/P2. Rapid photospheric flux cancellation (duration∼\sim20-30 min, rate≈\approx3.44×\times1020^{20} Mx h−1^{-1}) was observed during and even after the first B6.0 flare and continued until the end of the second C2.3 flare. The RHESSI X-ray sources were located at the site of the loop's coalescence. To the best of our knowledge, such a clear interaction of chromospheric loops along with rapid flux cancellation has not been reported before. These high-resolution observations suggest the formation of a small flux rope by a series of magnetic reconnection within chromospheric loops associated with very rapid flux cancellation.Comment: A&A, in press, 12 pages, 12 figure

    Magnon topology and thermal Hall effect in trimerized triangular lattice antiferromagnet

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    The non-trivial magnon band topology and its consequent responses have been extensively studied in two-dimensional magnetisms. However, the triangular lattice antiferromagnet (TLAF), the best-known frustrated two-dimensional magnet, has received less attention than the closely related Kagome system, because of the spin-chirality cancellation in the umbrella ground state of the undistorted TLAF. In this work, we study the band topology and the thermal Hall effect (THE) of the TLAF with (anti-)trimerization distortion under the external perpendicular magnetic field using the linearized spin wave theory. We show that the spin-chirality cancellation is removed in such case, giving rise to the non-trivial magnon band topology and the finite THE. Moreover, the magnon bands exhibit band topology transitions tuned by the magnetic field. We demonstrate that such transitions are accompanied by the logarithmic divergence of the first derivative of the thermal Hall conductivity. Finally, we examine the above consequences by calculating the THE in the hexagonal manganite YMnO3_3, well known to have anti-trimerization.Comment: 6 + 7 pages, 3 + 5 figures, 0 + 1 table; Journal reference adde

    On Hyperelastic Crease

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    We present analyses of crease-formation and stability criteria for incompressible hyperelastic solids. A generic singular perturbation over a laterally compressed half-space creates a far-field eigenmode of three energy-release angular sectors separated by two energy-elevating sectors of incremental deformation. The far-field eigenmode braces the energy-release field of the surface flaw against the transition to a self-similar crease field, and the braced-incremental-deformation (bid) field has a unique shape factor that determines the creasing stability. The shape factor, which is identified by two conservation integrals that represent a subsurface dislocation in the tangential manifold, is a monotonically increasing function of compressive strain. For Neo-Hookean material, when the shape factor is below unity, the bid field is configurationally stable. When the compressive strain is 0.356, the shape factor becomes unity, and the bid field undergoes a higher-order transition to a crease field. At the crease-limit point, we have two asymptotic solutions of the crease-tip folding field and the leading-order far field with two scaling parameters, the ratio of which is determined by matched asymptotes. Our analyses show that the surface is stable against singular perturbation up to the crease limit point and becomes unstable beyond the limit. However, the flat state is metastable against a regular perturbation between the crease limit point and wrinkle critical point, which is a first-order instability point. We introduced a novel finite element method for simulating the bid field with a finite domain size. For Gent model, the strain-stiffening alters the shape factor dependence on the compressive strain, raising crease resistance. The new findings in crease mechanisms will help study ruga mechanics of self-organization and design soft-material structures for high crease resistance.Comment: 42 pages, 6 figure
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