6,764 research outputs found

    The Cauchy problem for the Pavlov equation

    Full text link
    Commutation of multidimensional vector fields leads to integrable nonlinear dispersionless PDEs arising in various problems of mathematical physics and intensively studied in the recent literature. This report is aiming to solve the scattering and inverse scattering problem for integrable dispersionless PDEs, recently introduced just at a formal level, concentrating on the prototypical example of the Pavlov equation, and to justify an existence theorem for global bounded solutions of the associated Cauchy problem with small data.Comment: In the new version the analytical technique was essentially revised. The previous version contained a wrong statement about the solvability of the inverse problem for large data. This problem remains ope

    Microscopic theory of multipole ordering in NpO2

    Full text link
    In order to examine the mysterious ordered phase of NpO2 from a microscopic viewpoint, we investigate an f-electron model on an fcc lattice constructed based on a j-j coupling scheme. First, an effective model with multipole interactions is derived in the strong-coupling limit. Numerical analysis of the model clearly indicates that the interactions for \Gamma_{4u} and \Gamma_{5u} moments are relevant to the ground state. Then, by applying mean-field theory to the simplified model including only such interactions, we conclude that longitudinal triple-q \Gamma_{5u} octupole order is realized in NpO2 through the combined effects of multipole interactions and anisotropy of the \Gamma_{5u} moment.Comment: 5 pages, 2 figure

    Economic and demographic issues related to deployment of the Satellite Power System (SPS)

    Get PDF
    Growth in energy consumption stimulated interest in exploitation of renewable sources of electric energy. One technology that was proposed is the Satellite Power System (SPS). Before committing the U.S. to such a large program, the Department of Energy and the National Aeronautics and Space Administration are jointly participating in an SPS Concept Development and Evaluation Program. This white paper on industrial and population relocation is part of the FY 78 preliminary evaluation of related socio-economic issues. Results of four preliminary assessment activities are documented

    The PEP Survey: Infrared Properties of Radio-Selected AGN

    Full text link
    By exploiting the VLA-COSMOS and the Herschel-PEP surveys, we investigate the Far Infrared (FIR) properties of radio-selected AGN. To this purpose, from VLA-COSMOS we considered the 1537, F[1.4 GHz]>0.06 mJy sources with a reliable redshift estimate, and sub-divided them into star-forming galaxies and AGN solely on the basis of their radio luminosity. The AGN sample is complete with respect to radio selection at all z<~3.5. 832 radio sources have a counterpart in the PEP catalogue. 175 are AGN. Their redshift distribution closely resembles that of the total radio-selected AGN population, and exhibits two marked peaks at z~0.9 and z~2.5. We find that the probability for a radio-selected AGN to be detected at FIR wavelengths is both a function of radio power and redshift, whereby powerful sources are more likely to be FIR emitters at earlier epochs. This is due to two distinct effects: 1) at all radio luminosities, FIR activity monotonically increases with look-back time and 2) radio activity of AGN origin is increasingly less effective at inhibiting FIR emission. Radio-selected AGN with FIR emission are preferentially located in galaxies which are smaller than those hosting FIR-inactive sources. Furthermore, at all z<~2, there seems to be a preferential (stellar) mass scale M ~[10^{10}-10^{11}] Msun which maximizes the chances for FIR emission. We find such FIR (and MIR) emission to be due to processes indistinguishable from those which power star-forming galaxies. It follows that radio emission in at least 35% of the entire AGN population is the sum of two contributions: AGN accretion and star-forming processes within the host galaxy.Comment: 13 pages, 14 figures, to appear in MNRA

    A new player in the development of TRAIL based therapies for hepatocarcinoma treatment: ATM kinase

    Get PDF
    Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. HCCs are genetically and phenotypically heterogeneous tumors characterized by very poor prognosis, mainly due to the lack, at present, of effective therapeutic options, as these tumors are rarely suitable for radiotherapy and often resistant to chemotherapy protocols. In the last years, agonists targeting the Tumor Necrosis Factor Related Apoptosis Inducing Ligand (TRAIL) death receptor, has been investigated as a valuable promise for cancer therapy, based on their selectivity for malignant cells and low toxicity for healthy cells. However, many cancer models display resistance to death receptor induced apoptosis, pointing to the requirement for the development of combined therapeutic approaches aimed to selectively sensitize cancer cells to TRAIL. Recently, we identified ATM kinase as a novel modulator of the ability of chemotherapeutic agents to enhance TRAIL sensitivity. Here, we review the biological determinants of HCC responsiveness to TRAIL and provide an exhaustive and updated analysis of the molecular mechanisms exploited for combined therapy in this context. The role of ATM kinase as potential novel predictive biomarker for combined therapeutic approaches based on TRAIL and chemotherapeutic drugs will be closely discussed

    An automatic deep learning approach for coronary artery calcium segmentation

    Full text link
    Coronary artery calcium (CAC) is a significant marker of atherosclerosis and cardiovascular events. In this work we present a system for the automatic quantification of calcium score in ECG-triggered non-contrast enhanced cardiac computed tomography (CT) images. The proposed system uses a supervised deep learning algorithm, i.e. convolutional neural network (CNN) for the segmentation and classification of candidate lesions as coronary or not, previously extracted in the region of the heart using a cardiac atlas. We trained our network with 45 CT volumes; 18 volumes were used to validate the model and 56 to test it. Individual lesions were detected with a sensitivity of 91.24%, a specificity of 95.37% and a positive predicted value (PPV) of 90.5%; comparing calcium score obtained by the system and calcium score manually evaluated by an expert operator, a Pearson coefficient of 0.983 was obtained. A high agreement (Cohen's k = 0.879) between manual and automatic risk prediction was also observed. These results demonstrated that convolutional neural networks can be effectively applied for the automatic segmentation and classification of coronary calcifications

    Comparison of energy consumption and costs of different HEVs and PHEVs in European and American context

    Get PDF
    This paper will analyse on the one hand the potential of Plug in Hybrid electric Vehicles to significantly reduce fuel consumption and displace it torward various primary energies thanks to the electricity sector. On the other hand the total cost of ownership of two different PHEV architectures will be compared to a conventional cehicle and a HEV without external charging

    Complementarity relation for irreversible processes near steady states

    Get PDF
    A relation giving a minimum for the irreversible work in quasi-equilibrium processes was derived by Sekimoto et al. [K. Sekimoto, S. Sasa, J. Phys. Soc. Japan 66 (1997) 3326] in the framework of stochastic energetics. This relation can also be written as a type of “uncertainty principle” in such a way that the precise determination of the Helmholtz free energy through the observation of the work 〈W〉 requires an indefinitely large experimental time Δt. In the present article, we extend this relation to the case of quasi-steady processes by using the concept of non-equilibrium Helmholtz free energy. We give a formulation of the second law for these processes that extends that presented by Sekimoto [K. Sekimoto, Prog. Theoret. Phys. Suppl. No. 130 (1998) 17] by a term of the first order in the inverse of the experimental time. As an application of our results, two possible experimental situations are considered: stretching of a RNA molecule and the drag of a dipolar particle in the presence of a gradient of electric force.Fil: Santini, E. Comissão Nacional de Energia Nuclear; Brasil. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Centro Brasileiro de Pesquisas Físicas; BrasilFil: Carusela, María Florencia. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Izquierdo, E. D.. Universidad de Buenos Aires. Ciclo Básico Común; Argentina. Universidad de Buenos Aires. Facultad de Agronomia; Argentin

    A Bell-Evans-Polanyi principle for molecular dynamics trajectories and its implications for global optimization

    Full text link
    The Bell-Evans-Polanyi principle that is valid for a chemical reaction that proceeds along the reaction coordinate over the transition state is extended to molecular dynamics trajectories that in general do not cross the dividing surface between the initial and the final local minima at the exact transition state. Our molecular dynamics Bell-Evans-Polanyi principle states that low energy molecular dynamics trajectories are more likely to lead into the basin of attraction of a low energy local minimum than high energy trajectories. In the context of global optimization schemes based on molecular dynamics our molecular dynamics Bell-Evans-Polanyi principle implies that using low energy trajectories one needs to visit a smaller number of distinguishable local minima before finding the global minimum than when using high energy trajectories
    corecore