3,477 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

    Persistent Non-pharmacological Pain Management and Brain-Predicted Age Differences in Middle-Aged and Older Adults With Chronic Knee Pain

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    Chronic pain has been associated with changes in pain-related brain structure and function, including advanced brain aging. Non-pharmacological pain management is central to effective pain management. However, it is currently unknown how use of non-pharmacological pain management is associated with pain-related brain changes. The objective of the current study was to examine the association between brain-predicted age difference and use of non-pharmacological pain management (NPM) in a sample of middle-aged and older adults with and without chronic knee pain across two time points. One-hundred and 12 adults (mean age = 57.9 ± 8.2 years) completed sociodemographic measures, clinical pain measures, structural T1-weighted brain magnetic resonance imaging, and self-reported non-pharmacological pain management. Using a validated approach, we estimated a brain-predicted age difference (brain-PAD) biomarker, calculated as brain-predicted age minus chronological age, and the change in brain-PAD across 2 years. Repeated measures analysis of covariance was conducted to determine associations of non-pharmacological pain management and brain-PAD, adjusting for age, sex, study site, and clinical pain. There was a significant time*pain/NPM interaction effect in brain-PAD (p < 0.05). Tests of simple main effects indicated that those persistently using NPM had a “younger” brain-PAD over time, suggesting a potential protective factor in persistent NPM use. Future studies are warranted to determine the influence of NPM in brain aging and pain-related neurological changes

    Addressing Pain Using a Mediterranean Ketogenic Nutrition Program in Older Adults with Mild Cognitive Impairment

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    Kamelia Klejc,1 Yenisel Cruz-Almeida,2 Julia L Sheffler1 1Center for Translational Behavioral Science, Florida State University College of Medicine, Tallahassee, FL, USA; 2Center for Cognitive Aging and Memory, University of Florida, Gainesville, FL, USACorrespondence: Julia L Sheffler, Email [email protected]: Chronic pain has negative physical and cognitive consequences in older adults and may lead to a poorer quality of life. Mediterranean ketogenic nutrition (MKN) is a promising nonpharmacological intervention for pain management, but long-term adherence is challenging due to the carbohydrate restrictive diet regimen. The main objective of this study was to evaluate the effects of the pilot MKN Adherence (MKNA) Program on pain in older adults with mild cognitive impairment and to assess whether improvements in self-reported pain were associated with adherence to MKN. Older adults (N = 58) aged 60– 85 with possible mild cognitive impairment were randomized to a 6-week MKNA arm or an MKN Education (MKNE) program arm. Both arms received the same nutrition education and group format; however, the MKNA arm received additional motivational interviewing and cognitive behavioral skills to enhance adherence. Changes in self-reported pain (Brief Pain Inventory, Roland Morris, Patient’s Global Impression of Change) and adherence to MKN (ketone levels, self-reported adherence) were assessed at baseline, 6-weeks, and 3-months post intervention. Both arms showed clinically significant reductions in pain. Greater adherence to MKN across the 6-week intervention was associated with higher ratings of pain-related changes on the Patient’s Global Impression of Change scale. Based on these findings, adherence to MKN may promote improvements in self-reported pain in older adults with mild cognitive impairment and findings support the need for future full-scale randomized clinical trials evaluating MKN programs on pain. Trial Registration: Clinicaltrials.gov ID: NCT04817176Keywords: ketogenic diet, ketosis, chronic pain, adherence, nutrition progra

    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

    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

    Handling magnetic and structural properties of EuMnO3 thin films by the combined effect of Lu doping and substrate strain

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    This work aims to understand the alterations induced by film/substrate lattice mismatch in structure, lattice dynamics and magnetic response of orthorhombic Eu1-xLuxMnO3 thin films within the range 0 ≤ x ≤ 0.4, when compared to results reported for ceramics with analogous composition. Thin films, which have been deposited onto Pt/Ti/SiO2/Si(100) oriented substrates via chemical method, exhibit noteworthy modifications in the magnetic ordering properties and, contrary to ceramics, do not show any sharp phase transition to the paramagnetic state. This reveals an induced ferromagnetic response in the films which is stable up to 100 K. X-ray diffraction and Raman spectroscopy measurements have been performed to identify the mechanically compressive state induced by the substrate and Lu doping. This facilitates insight into the magnetoelastic coupling effect in these films which is driven by alterations in electronic orbital overlapping and the associated antiferromagnetic superexchange interactions.publishe

    A Transfer Matrix Method for Resonances in Randall-Sundrum Models

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    In this paper we discuss in detail a numerical method to study resonances in membranes generated by domain walls in Randall-Sundrum-like scenarios. It is based on similar works to understand the quantum mechanics of electrons subject to the potential barriers that exist in heterostructures in semiconductors. This method was used recently to study resonances of a three form field and lately generalized to arbitrary forms. We apply it to a lot of important models, namely those that contain the Gauge, Gravity and Spinor fields. In many cases we find a rich structure of resonances which depends on the parameters involved.Comment: 25 pages, 17 figure

    Variable exponent Besov-Morrey spaces

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    In this paper we introduce Besov-Morrey spaces with all indices variable and study some fundamental properties. This includes a description in terms of Peetre maximal functions and atomic and molecular decompositions. This new scale of non-standard function spaces requires the introduction of variable exponent mixed Morrey-sequence spaces, which in turn are defined within the framework of semimodular spaces. In particular, we obtain a convolution inequality involving special radial kernels, which proves to be a key tool in this work.publishe
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