690 research outputs found

    LP-VIcode: a program to compute a suite of variational chaos indicators

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    An important point in analysing the dynamics of a given stellar or planetary system is the reliable identification of the chaotic or regular behaviour of its orbits. We introduce here the program LP-VIcode, a fully operational code which efficiently computes a suite of ten variational chaos indicators for dynamical systems in any number of dimensions. The user may choose to simultaneously compute any number of chaos indicators among the following: the Lyapunov Exponents, the Mean Exponential Growth factor of Nearby Orbits, the Slope Estimation of the largest Lyapunov Characteristic Exponent, the Smaller ALignment Index, the Generalized ALignment Index, the Fast Lyapunov Indicator, the Othogonal Fast Lyapunov Indicator, the dynamical Spectra of Stretching Numbers, the Spectral Distance, and the Relative Lyapunov Indicator. They are combined in an efficient way, allowing the sharing of differential equations whenever this is possible, and the individual stopping of their computation when any of them saturates.Comment: 26 pages, 9 black-and-white figures. Accepted for publication in Astronomy and Computing (Elsevier

    Metástasis musculares del adenocarcinoma renal

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    El carcinoma renal puede producir metástasis, siendo las más frecuentes en pulmón, hígado, esqueleto y encéfalo. Las metástasis aisladas en el músculo esquelético son muy raras, existiendo alrededor de veinte casos publicados en la literatura. Presentamos dos casos de metástasis de carcinoma renal, localizadas en el músculo esquelético. Es importante el diagnóstico diferencial de estas metástasis con los sarcomas de partes blandas, ya que su tratamiento y pronóstico son muy diferentes.The renal cell carcinoma can produce metastatic, the most common are in lung, liver, bones and encephalon. The isolated metastatic in muscle are unusual, there are only twenty cases published, most of them isolated cases. We present two cases of metastatic of renal cell carcinoma isolated in skeletal muscle. It is very important the differential diagnosis of this kind of lesions with soft tissue sarcomas because treatment and prognosis are very different

    Observation of phase noise reduction in photonically synthesized sub-THz signals using a passively mode-locked laser diode and highly selective optical filtering

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    A Continuous Wave (CW) sub-THz photonic synthesis setup based on a single Passively Mode-Locked Laser Diode (PMLLD) acting as a monolithic Optical Frequency Comb Generator (OFCG) and highly selective optical filtering has been implemented to evaluate the phase noise performance of the generated sub-THz signals. The analysis of the synthesized sub-THz signals up to 120 GHz gives as a result an effective reduction of the electrical linewidth when compared to direct harmonic generation that begins at 50 GHz and becomes greater as the frequency increases. The phase noise reduction offered by the setup, along with its integration potential, cost and bandwidth, make it a promising candidate to the development of an integrated and high performance low phase noise local oscillator in the sub-THz range.Work supported by the Spanish Ministry of Science and Technology through the project TEC2009-14525-C02-02 and by the European Commission FP7 iPHOS Project. The work by A.R. Criado has been supported by the Spanish Ministry of Science and Technology under the FPI Program, Grant# BES2010-030290.Publicad

    Lipomas profundos

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    Se han revisado retrospectivamente 10 lipomas profundos localizados en los miembros. Todos los pacientes fueron intervenidos quirúrgicamente y el diagnóstico de certeza fue histopatológico. Siete de los casos eran lipomas intra o intermusculares y los restantes angiolipoma, hibernoma y fibrolipoma intraneural, respectivamente. El seguimiento medio postoperatorio fue de 48 meses (mínimo: 14, y máximo: 84). No ha habido recidiva en ningún caso.This article is a retrospective review of 10 deep lipomata localized in the limbs. In all the cases the treatment required surgery, and the diagnosis was made by histopathological analysis. Seven cases were intra or intermuscular lipomata, and the other three were angiolipoma, hibernoma and endoneural fibrolipoma. The average postoperative follow-up time was 48 months (14 min-84 max). None showed recurrence at review

    Global Waste Management Outlook

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    The Global Waste Management Outlook, a collective effort of the United Nations Environment Programme and the International Waste Management Association, is a pioneering scientific global assessment on the state of waste management and a call for action to the international community. Prepared as a follow up to the Rio+20 Summit and as a response to UNEP Governing Council decision GC 27/12, the document establishes the rationale and the tools for taking a holistic approach towards waste management and recognizing waste and resource management as a significant contributor to sustainable development and climate change mitigation. To complement the Sustainable Development Goals of the Post-2015 Development Agenda, the Outlook sets forth Global Waste Management Goals and a Global Call to Action to achieve those goals

    Comparison of Monolithic Optical Frequency Comb Generators Based on Passively Mode-Locked Lasers for Continuous Wave mm-Wave and Sub-THz Generation

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    In this paper, two different Passive Mode-Locked Laser Diodes (PMLLD) structures, a Fabry-Perot cavity and a ring cavity laser are characterized and evaluated as monolithic Optical Frequency Comb Generators (OFCG) for CW sub-THz generation. An extensive characterization of the devices under study is carried out based on an automated measurement system that systematically evaluates the dynamic characteristics of the devices, focusing on the figures of merit that define the optimum performance of a pulsed laser source when considered as an OFCG. Sub-THz signals generated with both devices at 60 GHz and 90 GHz are presented and analyzed in terms of electrical linewidth to compare such components for mm-Wave and sub-THz photonic generation. This work offers a systematic comparison of PMLLD devices for OFCG operation and provides reference information of the performance of two different device topologies that can be used for the implementation of photonic integrated sub-THz CW generation.We acknowledge COBRA Research Institute, Eindhoven University of Technology, the Netherlands for the fabrication of the ring lasers within the joint European platform for InP-based components and circuits, JePPIX.Publicad

    Probing a regular orbit with spectral dynamics

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    We have extended the spectral dynamics formalism introduced by Binney & Spergel, and have implemented a semi-analytic method to represent regular orbits in any potential, making full use of their regularity. We use the spectral analysis code of Carpintero & Aguilar to determine the nature of an orbit (irregular, regular, resonant, periodic) from a short-time numerical integration. If the orbit is regular, we approximate it by a truncated Fourier time series of a few tens of terms per coordinate. Switching to a description in action-angle variables, this corresponds to a reconstruction of the underlying invariant torus. We then relate the uniform distribution of a regular orbit on its torus to the non-uniform distribution in the space of observables by a simple Jacobian transformation between the two sets of coordinates. This allows us to compute, in a cell-independent way, all the physical quantities needed in the study of the orbit, including the density and in the line-of-sight velocity distribution, with much increased accuracy. The resulting flexibility in the determination of the orbital properties, and the drastic reduction of storage space for the orbit library, provide a significant improvement in the practical application of Schwarzschild's orbit superposition method for constructing galaxy models. We test and apply our method to two-dimensional orbits in elongated discs, and to the meridional motion in axisymmetric potentials, and show that for a given accuracy, the spectral dynamics formalism requires an order of magnitude fewer computations than the more traditional approaches.Comment: 13 pages, 18 eps figures, submitted to MNRA

    Building up the Stellar Halo of the Galaxy

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    We study numerical simulations of satellite galaxy disruption in a potential resembling that of the Milky Way. Our goal is to assess whether a merger origin for the stellar halo would leave observable fossil structure in the phase-space distribution of nearby stars. We show how mixing of disrupted satellites can be quantified using a coarse-grained entropy. Although after 10 Gyr few obvious asymmetries remain in the distribution of particles in configuration space, strong correlations are still present in velocity space. We give a simple analytic description of these effects, based on a linearised treatment in action-angle variables, which shows how the kinematic and density structure of the debris stream changes with time. By applying this description we find that a single satellite of current luminosity 10^8 L_\sun disrupted 10 Gyr ago from an orbit circulating in the inner halo (mean apocentre 12\sim 12 kpc) would contribute about 30\sim 30 kinematically cold streams with internal velocity dispersions below 5 km/s to the local stellar halo. If the whole stellar halo were built by disrupted satellites, it should consist locally of 300 - 500 such streams. Clear detection of all these structures would require a sample of a few thousand stars with 3-D velocities accurate to better than 5 km/s. Even with velocity errors several times worse than this, the expected clumpiness should be quite evident. We apply our formalism to a group of stars detected near the North Galactic Pole, and derive an order of magnitude estimate for the initial properties of the progenitor system.Comment: 28 pages, 10 figures, minor changes, matches the version to appear in MNRAS, Vol. 307, p.495-517 (August 1999

    Idiopathic osteonecrosis of the medial tibial plateau

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    Osteonecrosis of the medial tibial plateau is characterized by acute pain on the medial aspect of the knee. Progression can lead to articular collapse and requires early diagnosis and treatment. We studied seven patients affected of idiopathic osteonecrosis of the tibial plateau. The mean age was 62 years and the mean follow-up 42 months. We performed roentgenograms in all patients, bone scans in three patients and magnetic resonance image (MRI) in five. MRI shows T1-weighted low-intensity signal and T2-weighted high-intensity signal with a surrounding area of intermediate low-intensity signal. An increased focal uptake was seen at bone scan. Histological findings showed necrotic bone with empty lacunae. Surgical treatment consisted of tibial subchondral drilling in four patients-two of them by failure of conservative treatment, and a total knee arthroplasty in other two. One patient had a satisfactory evolution with conservative treatment. Idiopathic osteonecrosis of the tibial plateau must be considered in elderly patients with knee pain over the medial tibial plateau. At early stages, decompression with tibial drilling must be considered. This procedure allows a prompt and effective relief of symptom
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