Analysis of the railway track as a spatially periodic structure

This article presents a new and computationally efficient method of analysis of a railway track modelled as a continuous beam of 2N spans supported by elastic vertical springs. The main feature of this method is its important reduction in computational effort with respect to standard matrix methods of structural analysis. In this article, the whole structure is considered to be a repetition of a single one. The analysis presented is applied to a simple railway track model, i.e. to a repetitive beam supported on vertical springs (sleepers). The proposed method of analysis is based on the general theory of spatially periodic structures. The main feature of this theory is the possibility to apply Discrete Fourier Transform (DFT) in order to reduce a large system of q(2N + 1) linear stiffness equilibrium equations to a set of 2N + 1 uncoupled systems of q equations each. In this way, a dramatic reduction of the computational effort of solving the large system of equations is achieved. This fact is particularly important in the analysis of railway track structures, in which N is a very large number (around several thousands), and q = 2, the vertical displacement and rotation, is very small. The proposed method allows us to easily obtain the exact solution given by Samartín [1], i.e. the continuous beam railway track response. The comparison between the proposed method and other methods of analysis of railway tracks, such as Lorente de Nó and Zimmermann-Timoshenko, clearly shows the accuracy of the obtained results for the proposed method, even for low values of N. In addition, identical results between the proposed and the Lorente methods have been found, although the proposed method seems to be of simpler application and computationally more efficient than the Lorente one. Small but significative differences occur between these two methods and the one developed by Zimmermann-Timoshenko. This article also presents a detailed sensitivity analysis of the vertical displacement of the sleepers. Although standard matrix methods of structural analysis can handle this railway model, one of the objectives of this article is to show the efficiency of DFT method with respect to standard matrix structural analysis. A comparative analysis between standard matrix structural analysis and the proposed method (DFT), in terms of computational time, input, output and also software programming, will be carried out. Finally, a URL link to a MatLab computer program list, based on the proposed method, is give

Joint modelling of two sequential times to event with longitudinal information

In survival analysis, the lifetimes may be observed in some speci¯ed order, where the time to event Tk, cannot be observed until T1; :::; Tk¡1 have been observed. The present work proposes a joint model of two sequential times to events together with longitudinal information, extending the joint model of Wolfsohn and Tsiatis (1997) for one time to event and one longitudinal variable. We apply the model to the clinical trial called TIBET, in which an intermit- tent therapeutic strategy has been assigned to each patient. Of special clinical interest is the lifetime that a patient needs before restarting treatment given the progression of biological markers recorded during the followup period.Postprint (author’s final draft

BEACON: A Cloud Network Federation Framework

This paper presents the BEACON Framework, which will enable the provision and management of cross-site virtual networks for federated cloud infrastructures in order to support the automated deployment of applications and services across different clouds and datacenters. The proposed framework will support different federation architectures, going from tightly coupled (datacenter federation) to loosely coupled (cloud federation and multi-cloud orchestration) architectures, and will enable the creation of Layer 2 and Layer 3 overlay networks to interconnect remote resources located at different cloud sites. A high level description of the main components of the BEACON framework is also introduced

Viral expression and molecular profiling in liver tissue versus microdissected hepatocytes in hepatitis B virus - associated hepatocellular carcinoma

Abstract Background The molecular mechanisms whereby hepatitis B virus (HBV) induces hepatocellular carcinoma (HCC) remain elusive. We used genomic and molecular techniques to investigate host-virus interactions by studying multiple areas of the same liver from patients with HCC. Methods We compared the gene signature of whole liver tissue (WLT) versus laser capture-microdissected (LCM) hepatocytes along with the intrahepatic expression of HBV. Gene expression profiling was performed on up to 17 WLT specimens obtained at various distances from the tumor center from individual livers of 11 patients with HCC and on selected LCM samples. HBV markers in liver and serum were determined by real-time polymerase chain reaction (PCR) and confocal immunofluorescence. Results Analysis of 5 areas of the liver showed a sharp change in gene expression between the immediate perilesional area and tumor periphery that correlated with a significant decrease in the intrahepatic expression of HB surface antigen (HBsAg). The tumor was characterized by a large preponderance of down-regulated genes, mostly involved in the metabolism of lipids and fatty acids, glucose, amino acids and drugs, with down-regulation of pathways involved in the activation of PXR/RXR and PPARα/RXRα nuclear receptors, comprising PGC-1α and FOXO1, two key regulators critically involved not only in the metabolic functions of the liver but also in the life cycle of HBV, acting as essential transcription factors for viral gene expression. These findings were confirmed by gene expression of microdissected hepatocytes. Moreover, LCM of malignant hepatocytes also revealed up-regulation of unique genes associated with cancer and signaling pathways, including two novel HCC-associated cancer testis antigen genes, NUF2 and TTK. Conclusions Integrated gene expression profiling of whole liver tissue with that of microdissected hepatocytes demonstrated that HBV-associated HCC is characterized by a metabolism switch-off and by a significant reduction in HBsAg. LCM proved to be a critical tool to validate gene signatures associated with HCC and to identify genes that may play a role in hepatocarcinogenesis, opening new perspectives for the discovery of novel diagnostic markers and therapeutic targets

Mass Assembly of Stellar Systems and Their Evolution With the Sma (Masses). Multiplicity and the Physical Environment in L1448n

We present continuum and molecular line observations at 230 and 345 GHz from the Submillimeter Array (SMA) toward three protostars in the Perseus L1448N region. The data are from the large project "Mass Assembly of Stellar Systems and their Evolution with the SMA." Three dust continuum sources, Source B, Source NW, and Source A, are detected at both frequencies. These sources have corresponding emission peaks in C18O ($J=2\to 1$), 13CO ($J=2\to 1$), and HCO+ ($J=4\to 3$), and have offsets with N2D+ ($J=3\to 2$) peaks. High angular resolution data from a complementary continuum survey with the Karl G. Jansky Very Large Array show that Source B is associated with three 8 mm continuum objects, Source NW with two, and Source A remains single. These results suggest that multiplicity in L1448N exists at different spatial scales from a few thousand AU to <100 AU. Velocity gradients in each source obtained from two-dimensional fits to the SMA C18O emission are found to be perpendicular to within 20° of the outflow directions as revealed by 12CO ($J=2\to 1$). We have observed that Sources B and NW with multiplicity have higher densities than Source A without multiplicity. This suggests that thermal Jeans fragmentation can be relevant in the fragmentation process. However, we have not observed a difference in the ratio between rotational and gravitational energy between sources with and without multiplicity. We also have not observed a trend between non-thermal velocity dispersions and the level of fragmentation. Our study has provided the first direct and comprehensive comparison between multiplicity and core properties in low-mass protostars, although based on small number statistics.Astronom

A semi-parametric joint model for two sequential times to events and one longitudinal covariate

The present work proposes a joint model for two sequential times to events together with longitudinal information, as an extension of the joint model by Wolfsohn and Tsiatis (1997) for one time to event and one longitudinal variable. The model is applied to the TIBET, a clinical trial in which antiretroviral therapy interruptions guided by CD4 counts and plasma HIV-1 RNA levels in chronically HIV-1-infected patients are under evaluation. Details on the modelling strategy and the resulting estimates are givenPeer ReviewedPostprint (published version

Joint modelling of two sequential times to event with longitudinal information

In survival analysis, the lifetimes may be observed in some speci¯ed order, where the time to event Tk, cannot be observed until T1; :::; Tk¡1 have been observed. The present work proposes a joint model of two sequential times to events together with longitudinal information, extending the joint model of Wolfsohn and Tsiatis (1997) for one time to event and one longitudinal variable. We apply the model to the clinical trial called TIBET, in which an intermit- tent therapeutic strategy has been assigned to each patient. Of special clinical interest is the lifetime that a patient needs before restarting treatment given the progression of biological markers recorded during the followup period

Joint modelling of two sequential times to event with longitudinal information

In survival analysis, the lifetimes may be observed in some speci¯ed order, where the time to event Tk, cannot be observed until T1; :::; Tk¡1 have been observed. The present work proposes a joint model of two sequential times to events together with longitudinal information, extending the joint model of Wolfsohn and Tsiatis (1997) for one time to event and one longitudinal variable. We apply the model to the clinical trial called TIBET, in which an intermit- tent therapeutic strategy has been assigned to each patient. Of special clinical interest is the lifetime that a patient needs before restarting treatment given the progression of biological markers recorded during the followup period

Personalización de calzado en el punto de venta

The European project Fit4U has as aim stimulate the customization and the assistance for the selection of footwear based on the characteristics and needs of the user, improving this way the comfort and performance. Within a project which covers from the design and the manufacturing to the commercialization of the personalized product, the IBV has contributed with his experience in innovation orientated by the persons enabling the definition of technical specifications, which guide the development of new materials and components, and the development of two new tools: a methodology for the automatic design of customized lasts and a device to determine the biomechanical profile of the runner in the shop of a simple way.El proyecto europeo Fit4U tiene como objetivo impulsar la personalización y la asistencia para la selección de calzado basado en las características y necesidades del usuario, mejorando así las prestaciones de confort y rendimiento. Es un proyecto que cubre desde el diseño y la fabricación hasta la comercialización del producto personalizado. El Instituto de Biomecánica (IBV) ha aportado su experiencia en innovación orientada por las personas, que ha servido para definir las especificaciones técnicas en el desarrollo de nuevos materiales y componentes, y de dos nuevas herramientas: una metodología para el diseño automatizado de hormas personalizadas y un equipo capaz de determinar, de forma sencilla, el perfil biomecánico del corredor en la tienda