7,092 research outputs found

    Results in Kalb-Ramond field localization and resonances on deformed branes

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    We make an analysis about several aspects of localization of the Kalb-Ramond gauge field in a specific four dimensional AdS membrane embedded in a five dimensional space-time. The membrane is generated from a deformation of the λϕ4\lambda \phi^4 potential and belongs to a new class of defect solutions. In this context we find resonance structures in the analysis of massive modes. The study of deformed defects is important because they contain internal structures and these may have implications to the way the background space-time is constructed and the way its curvature behaves. The main objective here is to observe the contributions of the deformation procedure to the resonances and the well known field localization methods.Comment: 6 pages, 7 figures, Latex with EPL macr

    Fermion localization on asymmetric two-field thick branes

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    In this paper we investigate the localization of fermions on asymmetric thick branes generated by two scalars ϕ\phi and χ\chi. In order to trap fermions on the asymmetric branes with kink-like warp factors, the couplings with the background scalars ηΨˉF(χ,ϕ)Ψ\eta\bar{\Psi}F(\chi,\phi)\Psi are introduced, where F(χ,ϕ)F(\chi,\phi) is a function of ϕ\phi and χ\chi. We find that the coupling ηΨˉχϕΨ\eta\bar{\Psi}\chi\phi\Psi do not support the localization of 4-dimensional fermions on the branes. While, for the case ηΨˉχΨ+ηΨˉϕΨ\eta\bar{\Psi}\chi\Psi+\eta'\bar{\Psi}\phi\Psi, which is the kink-fermion coupling corresponding to one-scalar-generated brane scenarios, the zero mode of left-handed fermions could be trapped on the branes under some conditions.Comment: v2: 11 pages, 4 figures, accepted by CQ

    Location Based Indoor and Outdoor Lightweight Activity Recognition System

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    In intelligent environments one of the most relevant information that can be gathered about users is their location. Their position can be easily captured without the need for a large infrastructure through devices such as smartphones or smartwatches that we easily carry around in our daily life, providing new opportunities and services in the field of pervasive computing and sensing. Location data can be very useful to infer additional information in some cases such as elderly or sick care, where inferring additional information such as the activities or types of activities they perform can provide daily indicators about their behavior and habits. To do so, we present a system able to infer user activities in indoor and outdoor environments using Global Positioning System (GPS) data together with open data sources such as OpenStreetMaps (OSM) to analyse the user’s daily activities, requiring a minimal infrastructure

    Scalar-Kinetic Branes

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    This work tries to find out thick brane solutions in braneworld scenarios described by a real scalar field in the presence of a scalar-kinetic term F(X,ϕ)=XϕmF(X,\phi)=X\phi^m with a single extra dimension, where X=12MϕMϕX=\frac12\nabla_M\phi\nabla^M\phi stands for the standard kinetic term and m=0,1,2m=0,1,2\cdots. We mainly consider bent branes, namely de Sitter and Anti-de Sitter four-dimensional slices. The solutions of a flat brane are obtained when taking the four-dimensional cosmological constant Λ40\Lambda_4\rightarrow 0. When the parameter m=0m=0, these solutions turn to those of the standard scenario. The localization and spectrum of graviton on these branes are also analyzed.Comment: 10 pages, no figures, accepted by EP

    Pair production of the heavy leptons in future high energy linear e^{+}e^{-} colliders

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    The littlest Higgs model with T-parity predicts the existence of the T-odd particles, which can only be produced in pair. We consider pair production of the T-odd leptons in future high energy linear e+ee^{+}e^{-} collider (ILCILC). Our numerical results show that, as long as the T-odd leptons are not too heavy, they can be copiously produced and their possible signals might be detected via the processes e+eLˉiLje^{+}e^{-}\to \bar{L}_{i}L_{j} in future ILCILC experiments.Comment: Discussions added, typos and references correcte

    Probing the lightest new gauge boson BHB_H in the littlest Higgs model via the processes γγffˉBH\gamma\gamma \to f\bar{f}B_H at the ILC

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    The neutral gauge boson BHB_H with the mass of hundreds GeV, is the lightest particle predicted by the littlest Higgs(LH) model, and such particle should be the first signal of the LH model at the planed ILC if it exists indeed. In this paper, we study some processes of the BHB_H production associated with the fermion pair at the ILC, i.e., γγffˉBH\gamma\gamma\to f\bar{f}B_{H}. The studies show that the most promising processes to detect BHB_H among γγffˉBH\gamma\gamma\to f\bar{f}B_{H} are γγl+lBH(l=e,μ)\gamma\gamma\to l'^+l'^-B_{H}(l'=e,\mu), and they can produce the sufficient signals in most parameter space preferred by the electroweak precision data at the ILC. On the other hand, the signal produced via the certain BHB_H decay modes is typical and such signal can be easily identified from the SM background. Therefore, BHB_H, the lightest gauge boson in the LH model would be detectable at the photon collider realized at the ILC.Comment: 12 pages, 4 figure

    LD Motif Recognition by Talin: Structure of the Talin-DLC1 Complex

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    Cell migration requires coordination between integrin-mediated cell adhesion to the extracellular matrix and force applied to adhesion sites. Talin plays a key role in coupling integrin receptors to the actomyosin contractile machinery, while deleted in liver cancer 1 (DLC1) is a Rho GAP that binds talin and regulates Rho, and therefore actomyosin contractility. We show that the LD motif of DLC1 forms a helix that binds to the four-helix bundle of the talin R8 domain in a canonical triple-helix arrangement. We demonstrate that the same R8 surface interacts with the paxillin LD1 and LD2 motifs. We identify key charged residues that stabilize the R8 interactions with LD motifs and demonstrate their importance in vitro and in cells. Our results suggest a network of competitive interactions in adhesion complexes that involve LD motifs, and identify mutations that can be used to analyze the biological roles of specific protein-protein interactions in cell migration

    Chandra High Energy Grating Observations of the Fe Ka Line Core in Type 2 Seyfert Galaxies: A Comparison with Type 1 Nuclei

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    We present a study of the core of the Fe Ka emission line at ~6.4 keV in a sample of type II Seyfert galaxies observed by the Chandra High Energy Grating (HEG). The sample consists of 29 observations of 10 unique sources. We present measurements of the Fe Ka line parameters with the highest spectral resolution currently available. In particular, we derive the most robust intrinsic line widths for some of the sources in the sample to date. We obtained a weighted mean FWHM of 2000 \pm 160 km/s for 8 out of 10 sources (the remaining sources had insufficient signal-to-noise). From a comparison with the optical emission-line widths obtained from spectropolarimetric observations, we found that the location of Fe Ka line-emitting material is a factor of ~0.7-11 times the size of the optical BLR. Furthermore, compared to 13 type I AGNs for which the best Fe Ka line FWHM constraints were obtained, we found no difference in the FWHM distribution or the mean FWHM, and this conclusion is independent of the central black hole mass. This result suggests that the bulk of the Fe Ka line emission may originate from a universal region at the same radius with respect to the gravitational radius, ~30,000 Rg on average. By examining the correlation between the Fe Ka luminosity and the [O IV] line luminosity, we found a marginal difference in the Fe K line flux between type I and type II AGNs, but the spread in the ratio of L(Fe) to L([O IV]) is about two orders of magnitude. Our results confirm the theoretical expectation that the Fe Ka emission-line luminosity cannot trivially be used as a proxy of the intrinsic AGN luminosity, unless a detailed comparison of the data with proper models is applied.Comment: 16 pages, 6 figures, and 2 tables, accepted for publication in Ap

    Information loss in local dissipation environments

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    The sensitivity of entanglement to the thermal and squeezed reservoirs' parameters is investigated regarding entanglement decay and what is called sudden-death of entanglement, ESD, for a system of two qubit pairs. The dynamics of information is investigated by means of the information disturbance and exchange information. We show that for squeezed reservoir, we can keep both of the entanglement and information survival for a long time. The sudden death of information is seen in the case of thermal reservoir
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