8,121 research outputs found
BV-BFV approach to General Relativity, Einstein-Hilbert action
The present paper shows that general relativity in the Arnowitt-Deser-Misner
formalism admits a BV-BFV formulation. More precisely, for any
(pseudo-) Riemannian manifold M with space-like or time-like boundary
components, the BV data on the bulk induces compatible BFV data on the
boundary. As a byproduct, the usual canonical formulation of general relativity
is recovered in a straightforward way.Comment: 16 page
Classical BV theories on manifolds with boundary
In this paper we extend the classical BV framework to gauge theories on
spacetime manifolds with boundary. In particular, we connect the BV
construction in the bulk with the BFV construction on the boundary and we
develop its extension to strata of higher codimension in the case of manifolds
with corners. We present several examples including electrodynamics, Yang-Mills
theory and topological field theories coming from the AKSZ construction, in
particular, the Chern-Simons theory, the theory, and the Poisson sigma
model. This paper is the first step towards developing the perturbative
quantization of such theories on manifolds with boundary in a way consistent
with gluing.Comment: The second version has many typos corrected, references added. Some
typos are probably still there, in particular, signs in examples. In the
third version more typoes are corrected and the exposition is slightly
change
Exchange rate pass-through to import prices in South Africa: Is there asymmetry?
There is growing emphasis on the role played by the private sector in alleviating poverty in Africa. At the same time, greater focus is being placed on cash transfers as a poverty alleviation tool. This paper provides an economic rationale for private sector involvement in the provision of cash transfers. Previous research has focused on how the financial sector can provide payment solutions. In addition to payment mechanisms, the paper examines other avenues through which the private sector can contribute to cash transfer programmes .business taxes and Corporate Social Responsibility (CSR). Reducing corruption in tax administration and an enabling investment climate are essential if business taxes are to be a sustainable financing source for cash transfers. Governments can incorporate CSR into national policies and strategies which identify cash transfers as a poverty alleviation instrument. Cell phone banking, mobile branches, Point of sale (POS) technology and low cost banking are increasing access to financial services by the poor. These financial innovations can be used to make cash transfer payments.Exchange rate pass-through, Asymmetric pass-through, VECM, South Africa
The Relative Space: Space Measurements on a Rotating Platform
We introduce here the concept of relative space, an extended 3-space which is
recognized as the only space having an operational meaning in the study of the
space geometry of a rotating disk. Accordingly, we illustrate how space
measurements are performed in the relative space, and we show that an old-aged
puzzling problem, that is the Ehrenfest's paradox, is explained in this purely
relativistic context. Furthermore, we illustrate the kinematical origin of the
tangential dilation which is responsible for the solution of the Ehrenfest's
paradox.Comment: 14 pages, 2 EPS figures, LaTeX, to appear in the European Journal of
Physic
THE CRP BALANCING ACT: TRADING OFF COSTS AND MULTIPLE ENVIRONMENTAL BENEFITS
The Environmental Benefits Index (EBI) ranks Conservation Reserve Program (CRP) offers by weighing program costs for enrolling land in CRP against six environmental objectives. This paper uses Monte Carlo simulations to analyze the sensitivity of CRP enrollment outcome to the specification of the EBI. Results indicate that:(a)there is no major shift in average benefits throughout the U.S. when marginal changes in the weights occur, and (b) priority area weights, whether National or State, play a role in shifting CRP away from its traditional focus on highly erodible land, and (c) there is complementarity between the enduring benefits and the wildlife objectives and substitutability between the enduring benefits and the erosion reduction objectives;Environmental Economics and Policy, Land Economics/Use,
Not all visual symmetry is equal: partially distinct neural bases for vertical and horizontal symmetry
Visual mirror symmetry plays an important role in visual perception in both human and animal vision; its importance is reflected in the fact that it can be extracted automatically during early stages of visual processing. However, how this extraction is implemented at the cortical level remains an open question. Given the importance of symmetry in visual perception, one possibility is that there is a network which extracts all types of symmetry irrespective of axis of orientation; alternatively, symmetry along different axes might be encoded by different brain regions, implying that that there is no single neural mechanism for symmetry processing. Here we used fMRI-guided transcranial magnetic stimulation (TMS) to compare the neural basis of the two main types of symmetry found in the natural world, vertical and horizontal symmetry. TMS was applied over either right Lateral Occipital Cortex (LO), right Occipital Face Area (OFA) or Vertex while participants were asked to detect symmetry in low-level dot configurations. Whereas detection of vertical symmetry was impaired by TMS over both LO and OFA, detection of horizontal symmetry was delayed by stimulation of LO only. Thus, different types of visual symmetry rely on partially distinct cortical networks
TMS over right OFA affects individuation of faces but not of exemplars of objects
In addition to its well-documented role in processing of faces, the occipital face area in the right hemisphere (rOFA) may also play a role in identifying specific individuals within a class of objects. Here we explored this issue by using fMRI-guided TMS. In a first experiment, participants had to judge whether two sequentially presented images of faces or objects represented exactly the same exemplar or two different exemplars of the same class, while receiving online TMS over either the rOFA, the right lateral occipital cortex (rLO) or the Vertex (control). We found that, relative to Vertex, stimulation of rOFA impaired individuation of faces only, with no effect on objects; in contrast, TMS over rLO reduced individuation of objects but not of faces. In a second control experiment participants judged whether a picture representing a fragment of a stimulus belonged or not to the subsequently presented image of a whole stimulus (part-whole matching task). Our results showed that rOFA stimulation selectively disrupted performance with faces, whereas performance with objects (but not with faces) was selectively affected by TMS over rLO. Overall, our findings suggest that rOFA does not contribute to discriminate between exemplars of non-face objects
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