8,704 research outputs found
Differential Regularization of a Non-relativistic Anyon Model
Differential regularization is applied to a field theory of a
non-relativistic charged boson field with
self-interaction and coupling to a statistics-changing Chern-Simons
gauge field. Renormalized configuration-space amplitudes for all diagrams
contributing to the 4-point function, which
is the only primitively divergent Green's function, are obtained up to 3-loop
order. The renormalization group equations are explicitly checked, and the
scheme dependence of the -function is investigated. If the
renormalization scheme is fixed to agree with a previous 1-loop calculation,
the 2- and 3-loop contributions to vanish, and
itself vanishes when the ``self-dual'' condition relating
to the gauge coupling is imposed.Comment: 22 pages in ReVTEX (with a plaintext PostScript figure appended at
end), MIT CTP #221
Current trends of accelerometry to assess physical activity
Evaluar la actividad fÃsica de forma precisa y fiable sigue siendo un importante reto para los epidemiólogos, cientÃficos, médicos, especialistas en ejercicio e investigadores del comportamiento. Para ello, actualmente, los acelerómetros son dispositivos ampliamente utilizados en investigación cientÃfica. En el presente artÃculo se pretende dar muestra de cuál es la situación actual del uso de la acelerometrÃa para cuantificar niveles de actividad fÃsica. Asà como sus limitaciones y perspectivas de futuro con el fin de contribuir a su mejor uso
Titling and beyond: Evidence from Dar es Salaam, Tanzania
Land titling has been a policy priority for developing country cities for decades. In Sub-Saharan Africa and across the world, tenure formalization has been promoted as a tool to improve the quality and value of urban housing. The track record of these projects, however, has generally been disappointing. Why is this? In this paper, we argue that project design has paid too little attention to contextual features of land markets in estimating the benefits of formalization to individual households. We draw on evidence from a case study city – Dar es Salaam, Tanzania – to show that in cities where broader property rights institutions are incomplete and informal sources of tenure security are strong, formal property rights may not be valued by households. This raises questions about the households’ willingness to pay for regularisation and suggests that complementary strategies to build trust in government and consolidate public benefits of titling will be needed to ensure that projects have a beneficial impact
The Near-Horizon Limit of the Extreme Rotating d=5 Black Hole as a Homogenous Spacetime
We show that the spacetime of the near-horizon limit of the extreme rotating
d=5 black hole, which is maximally supersymmetric in N=2,d=5 supergravity for
any value of the rotation parameter j in [-1,1], is locally isomorphic to a
homogeneous non-symmetric spacetime corresponding to an element of the
1-parameter family of coset spaces SO(2,1)x SO(3)/SO(2)_j in which the subgroup
SO(2)_j is a combination of the two SO(2) subgroups of SO(2,1) and SO(3).Comment: Some points clarified and misprints corrected. Version to be
published in Classical and Quantum Gravit
Bethe-Salpeter equation for doubly heavy baryons in the covariant instantaneous approximation
In the heavy quark limit, a doubly heavy baryon is regarded as composed of a
heavy diquark and a light quark. We establish the Bethe-Salpeter (BS) equations
for the heavy diquarks and the doubly heavy baryons, respectively, to leading
order in a expansion. The BS equations are solved numerically under
the covariant instantaneous approximation with the kernels containing scalar
confinement and one-gluon-exchange terms. The masses for the heavy diquarks and
the doubly heavy baryons are obtained and the non-leptonic decay widths for the
doubly heavy baryons emitting a pseudo-scalar meson are calculated within the
model.Comment: Corrections to the text, two references added, version accepted for
publication in Physical Review
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