27 research outputs found
A Pyramid Scheme for Particle Physics
We introduce a new model, the Pyramid Scheme, of direct mediation of SUSY
breaking, which is compatible with the idea of Cosmological SUSY Breaking
(CSB). It uses the trinification scheme of grand unification and avoids
problems with Landau poles in standard model gauge couplings. It also avoids
problems, which have recently come to light, associated with rapid stellar
cooling due to emission of the pseudo Nambu-Goldstone Boson (PNGB) of
spontaneously broken hidden sector baryon number. With a certain pattern of
R-symmetry breaking masses, a pattern more or less required by CSB, the Pyramid
Scheme leads to a dark matter candidate that decays predominantly into leptons,
with cross sections compatible with a variety of recent observations. The dark
matter particle is not a thermal WIMP but a particle with new strong
interactions, produced in the late decay of some other scalar, perhaps the
superpartner of the QCD axion, with a reheat temperature in the TeV range. This
is compatible with a variety of scenarios for baryogenesis, including some
novel ones which exploit specific features of the Pyramid Scheme.Comment: JHEP Latex, 32 pages, 1 figur
Pesquisa de enterobactérias em patos domésticos (Cairina moschata) de propriedades localizadas em quatro municípios do Ceará, Brasil
Analysis of event-related fmri data using diffusion maps
Abstract. The blood oxygen level-dependent (BOLD) signal in response to brief periods of stimulus can be detected using event-related functional magnetic resonance imaging (ER-fMRI). In this paper, we propose a new approach for the analysis of ER-fMRI data. We regard the time series as vectors in a high dimensional space (the dimension is the number of time samples). We believe that all activated times series share a common structure and all belong to a low dimensional manifold. On the other hand, we expect the background time series (after detrending) to form a cloud around the origin. We construct an embedding that reveals the organization of the data into an activated manifold and a cluster of non-activated time series. We use a graph partitioning technique–the normalized cut to find the separation between the activated manifold and the background time series. We have conducted several experiments with synthetic and in-vivo data that demonstrate the performance of our approach.