1,659 research outputs found

    Modulated Inflation

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    We have studied modulated inflation that generates curvature perturbation from light-field fluctuation. As discussed in previous works, even if the fluctuation of the inflaton itself does not generate the curvature perturbation at the horizon crossing, fluctuation of a light field may induce fluctuation for the end-line of inflation and this may lead to generation of cosmological perturbation ``at the end of the inflation''. Our scenario is different from those that are based on the fluctuations of the boundary of the inflaton trajectory, as clearly explained in this paper by using the δN\delta N formalism. In this paper, we will consider the perturbation of the inflaton velocity that can be induced by a light field other than the inflaton. We also explain the crucial difference from the standard multi-field inflation model. We show concrete examples of the modulated inflation scenario in which non-gaussianity can be generated. We also discuss the running of the non-gaussianity parameter.Comment: 17pages, k^2/a^2 is included, accepted for publication in PL

    Dolor, calidad de vida y estado anĂ­mico relacionados con la salud de pacientes ancianos hospitalizado

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    Objetivo. A través de este estudio, se pretende establecer la relación existente entre la intensidad del dolor percibida, la ansiedad, depresión y calidad de vida de pacientes ancianos hospitalizados. Método. Presenta un diseño de tipo transversal descriptivo. El muestreo se realizó de manera aleatoria estratificada (119 participantes). Se evaluaron los niveles de ansiedad y depresión, así como la intensidad del dolor que los participantes reportaron durante la entrevista. Para esto, se utilizó la Escala de Ansiedad y Depresión de Goldberg (EADG), el cuestionario Perfil de Salud de Nottingham (PSN) y la Escala Verbal Simple (EVS). Resultados. En general, se observó que, en la medida en que el dolor aumentaba, empeoraban las áreas de calidad de vida evaluadas con el PSN, así como los niveles de ansiedad y depresión. Conclusión. Ante el deterioro de la calidad de vida y su relación con las respuestas emocionales asociadas a ansiedad y depresión, conforme la intensidad del dolor, se deben realizar intervenciones de nivel primario y secundario que permitan el control del dolor, con el fin de reducir el impacto en la salud mental de los adultos mayores, a partir de estrategias integradas entre lo farmacológico y psicológico. Del mismo modo, se sugiere la creación de programas intrahospitalarios que incorporen terapias integrales que, a su vez, atiendan la dimensión emocional y afectiva de los pacientes ancianos hospitalizados, con el propósito de mejorar su calidad de vida

    Large non-Gaussianity from two-component hybrid inflation

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    We study the generation of non-Gaussianity in models of hybrid inflation with two inflaton fields, (2-brid inflation). We analyse the region in the parameter and the initial condition space where a large non-Gaussianity may be generated during slow-roll inflation which is generally characterised by a large f_NL, tau_NL and a small g_NL. For certain parameter values we can satisfy tau_NL>>f_NL^2. The bispectrum is of the local type but may have a significant scale dependence. We show that the loop corrections to the power spectrum and bispectrum are suppressed during inflation, if one assume that the fields follow a classical background trajectory. We also include the effect of the waterfall field, which can lead to a significant change in the observables after the waterfall field is destabilised, depending on the couplings between the waterfall and inflaton fields.Comment: 16 pages, 6 figures; v2: comments and references added, typos corrected, matches published versio

    Elliptic Inflation: Generating the curvature perturbation without slow-roll

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    There are many inflationary models in which inflaton field does not satisfy the slow-roll condition. However, in such models, it is always difficult to generate the curvature perturbation during inflation. Thus, to generate the curvature perturbation, one must introduce another component to the theory. To cite a case, curvatons may generate dominant part of the curvature perturbation after inflation. However, we have a question whether it is unrealistic to consider the generation of the curvature perturbation during inflation without slow-roll. Assuming multi-field inflation, we encounter the generation of the curvature perturbation during inflation without slow-roll. The potential along equipotential surface is flat by definition and thus we do not have to worry about symmetry. We also discuss about KKLT models, in which corrections lifting the inflationary direction may not become a serious problem if there is a symmetry enhancement at the tip (not at the moving brane) of the inflationary throat.Comment: 27pages, 8figures, to appear in JCA

    Targeting ribosomal G-quadruplexes with naphthalene-diimides as RNA polymerase I inhibitors for colorectal cancer treatment

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    Guanine quadruplexes (G4s) are non-canonical nucleic acid structures commonly found in regulatory genomic regions. G4 targeting has emerged as a therapeutic approach in cancer. We have screened naph thalene-diimides (NDIs), a class of G4 ligands, in a cellular model of colorectal cancer (CRC). Here, we identify the leading compound T5 with a potent and selective inhibition of cell growth by high-affinity binding to G4s in ribosomal DNA, impairing RNA polymerase I (Pol I) elongation. Consequently, T5 induces a rapid inhibition of Pol I transcription, nucleolus disruption, proteasome-dependent Pol I catalytic subunit A degradation and autophagy. Moreover, we attribute the higher selectivity of carbohydrate-conjugated T5 for tumoral cells to its preferential uptake through the overexpressed glucose transporter 1. Finally, we succinctly demon strate that T5 could be explored as a therapeutic agent in a patient cohort with CRC. Therefore, we report a mode of action for these NDIs involving ribosomal G4 targeting

    Unraveling nanotopography of cell surface receptors

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    Cells communicate with their environment via surface receptors, but nanoscopic receptor organization with respect to complex cell surface morphology remains unclear. This is mainly due to a lack of accessible, robust and high-resolution methods. Here, we present an approach for mapping the topography of receptors at the cell surface with nanometer precision. The method involves coating glass coverslips with glycine, which preserves the fine membrane morphology while allowing immobilized cells to be positioned close to the optical surface. We developed an advanced and simplified algorithm for the analysis of single-molecule localization data acquired in a biplane detection scheme. These advancements enable direct and quantitative mapping of protein distribution on ruffled plasma membranes with near isotropic 3D nanometer resolution. As demonstrated successfully for CD4 and CD45 receptors, the described workflow is a straightforward quantitative technique to study molecules and their interactions at the complex surface nanomorphology of differentiated metazoan cells

    Small Stem Total Hip Arthroplasty in Hypoplasia of the Femur

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    Total hip arthroplasty in hypoplastic femurs is technically difficult and the incidence of complications and aseptic loosening is relatively high. Cemented, uncemented, off-the-shelf, and custom-made stems all have been advocated in these cases. From 1978 to 1997, we performed 86 total hip arthroplasties in 77 patients with a hypoplastic femur using a cemented, off-the-shelf, small, curved, cobalt-chromium stem. We hypothesized results equaled those of the identical but larger-sized stems in normal-sized femora which were used as comparisons. Clinical and radiographic evaluations were performed. Minimum followup was 4.2 years (mean, 12 years; range, 4.2–20.3 years); mean Harris hip score was 88, and mean hip flexion was 104°. Six stems were revised: four because of aseptic loosening, one after a femoral fracture, and one because of malpositioning. Complications included one perforation and one fracture of the femur, one fracture, one nonunion of the greater trochanter, and one deep infection. Implant survivorship for all hips at 15 years with aseptic revision of the stem as the end point was 90% (confidence interval, 82–99) which equaled results of the larger stems. The small off-the-shelf cemented Weber stem has a high long-term survival and a low complication rate. Survival compares favorably with other small-sized total hip systems

    Approach to map nanotopography of cell surface receptors

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    Cells communicate with their environment via surface receptors, but nanoscopic receptor organization with respect to complex cell surface morphology remains unclear. This is mainly due to a lack of accessible, robust and high-resolution methods. Here, we present an approach for mapping the topography of receptors at the cell surface with nanometer precision. The method involves coating glass coverslips with glycine, which preserves the fine membrane morphology while allowing immobilized cells to be positioned close to the optical surface. We developed an advanced and simplified algorithm for the analysis of single-molecule localization data acquired in a biplane detection scheme. These advancements enable direct and quantitative mapping of protein distribution on ruffled plasma membranes with near isotropic 3D nanometer resolution. As demonstrated successfully for CD4 and CD45 receptors, the described workflow is a straightforward quantitative technique to study molecules and their interactions at the complex surface nanomorphology of differentiated metazoan cells

    Search for the standard model Higgs boson at LEP

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