433 research outputs found
Quasinormal Modes and Choptuik Scaling in the Near Extremal Reissner-Nordstr{\"o} Black Hole
We study quasinormal modes of massless scalar and fermion fields in the near
extremal Reissner-Nordstr{\"o}m black hole, and relate them to Choptuik scaling
form following a recently proposed analytic approach. For both massless cases,
quasinormal modes are shown to be proportional to the black hole horizon and
the Hawking temperature, and the critical exponents are the same, although for
the fermionic case there are two possible discrete quasinormal modes. In
addition, the critical exponent of the massive boson is also equivalent to that
of the massless case. Finally, we discuss quasinormal modes and critical
exponents in the other models, and obtain some different critical exponents
between massless boson and massive one.Comment: 13 pages, Refs. and comments are added. To appear in Phys. Lett.
Dilaton driven Hawking radiation in AdS black hole
A recent study shows that Hawking radiation of the massless scalar field does
not appear on the two-dimensional AdS black hole background. We study this
issue by investigating absorption and reflection coefficients under dilaton
coupling with the matter field. If the scalar field does not couple to the
dilaton, then it is fully absorbed into the black hole without any outgoing
mode. On the other hand, once it couples to the dilaton field, the outgoing
mode of the massless scalar field exists and the nontrivial Hawking radiation
is obtained. Finally, we comment on this dilaton dependence of Hawking
radiation in connection with a three-dimensional black hole.Comment: 13 pages, revtex, no figures, version to appear in Phys. Lett.
Historicising intervention: Strategy and synchronicity in British intervention 1815-50
Copyright @ 2013 British International Studies Association.This article identifies three key themes in British intervention for purposes of liberal reordering in the period 1815â50, namely the âopening-upâ of new market spaces (discussed in relation to Uruguay/the Argentine Confederation in the 1840s), a cosmopolitan humanitarianism evident in the campaign for the abolition of the Atlantic slave trade that ran throughout this period, and the political-ideological contest between constitutionalist and absolutist forces and represented here by intervention in the Iberian Peninsula in the late 1820s to1830s. In developing a strategic perspective upon military/naval intervention the analysis shows its utility to have been subordinate to more fundamental sociopolitical, cultural, and institutional determinants. With regard to understanding the outcomes of specific intervention the analysis shows the importance of systematically evaluating developments in the domestic political environments of both intervening and target state as well as the military campaign itself and the need for sufficient general alignment or synchronisation in the timeline of developments in each of these three domains. This model helps to explain that whilst liberal interventions are not necessarily bound to fail, they frequently prove more difficult, complex, and protracted than the interveners expect
Decay Rate and Low-Energy Near-Horizon Dynamics of Acoustic Black Holes
We study the low-energy dynamics of an acoustic black hole near the sonic
horizon. For the experimental test of black hole evaporation in the laboratory,
the decay rate (greybody factor) of the acoustic black hole (sonic hole) can be
calculated by the usual low-energy perturbation method. As a consequence, we
obtain the decay rate of the sonic horizon from the absorption and the
reflection coefficients. Moreover, we show that the thermal emission from the
sonic horizon is only proportional to a control parameter which describes the
velocity of the fluid.Comment: 13pages, 3figures, RevTeX3, some minors corrected. version to appear
in PL
Urban assets and the financialisation fix: land tenure, renewal and path dependency in the city of Birmingham
Cities are places of incremental decision-making involving complex negotiations that produce accumulations of urban assets and path dependency. The ownership, control and co-ordination of urban land and its transformation into an investment asset is a key link between economic interests and urban activities that come together in site-based âfinancialisation fixesâ. A financialisation fix combines a development solution for a specific site with a financial model creating a locally embedded asset. This article examines how land tenure (freehold versus leasehold rights) influences the transformation of a city and the role a local authority plays in the financial management of land assets. This includes an analysis of the application of financialisation to urban assets and the first tax increment financing scheme of 1875
Absorption cross section and Hawking radiation in two-dimensional AdS black hole
We calculate the absorption coefficient of scalar field on the background of
the two-dimensional AdS black hole, which is of relevance to Hawking radiation.
For the massless scalar field, we find that there does not exist any massless
radiation.Comment: 6 pages, revtex, no figure
Using the Pathways Community HUB Care Coordination Model to Address Chronic Illnesses: A Case Study
Background/Objectives: Ohio communities are developing and expanding care coordination initiatives to integrate care for low-income pregnant women. Some of these initiatives are guided by the Pathways Community HUB model, which uses community healthworkers to address health, social, and behavioral risks for at-risk populations. This study documents the development, challenges andmanagement responses, and lessons learned from implementing a Pathways Community HUB care coordination program for anotherpopulation -- low-income adults with chronic disease risks.Methods: The study utilizes data extracted from the Care Coordination Systems (CCS) database used in Lucas County, Ohio between2015 and 2017 and interviews with program managers. Based on CCS data and insights from those interviewed, we describe the development and accomplishments of a Pathways Community HUB program for adults with chronic illnesses and identify challenges and lessons learned.Results: The Toledo/Lucas County program addressed more than half of 3,515 identified health and behavioral risks for 651 low-income adults in the program during its first two years of operation. Key challenges included building community support, establishing capacities to coordinate care, and sustaining the program over time. Establishing community networks to support program services and developing multiple funding sources are key lessons for long-term program sustainability.Conclusions: Documenting challenges and successes of existing programs and extracting lessons to guide implementation of similarpublic health efforts can potentially improve delivery of interventions. The Pathways Community HUB model has demonstrated success in addressing risks among at-risk adults. However, more comprehensive assessments of the model across different populations are warranted
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