851 research outputs found

    Regreso del pasado: Madame Lynch y el imaginario paraguayo

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    In the context of historical revisionism that characterized Latin American theater in the last two decades of the twentieth century, Milton Schinca wrote Madame Lynch (1989). This essay looks at two political readings of Lynch’s marginality in Paraguayan society, and of her relationship to power as a way of highlighting social constructs. It does so by analyzing the deliberate emphasis of the material conditions of Elisa Lynch, the function of her body, her use of visual and linguistic signs, the tension between power and marginality, and how monologues work as an attempt to deconstruct the patriarchal view of Madame Paraguay. This leads to a reading of the playtext as an attempt to reconsider Uruguay’s responsibility in the War of Paraguay (1865-1870). (AGR, Article in Spanish

    Small but long koch fractal monopole

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    A small but long wire fractal antenna based on the Koch curve is presented. Experimental and numerical results show that the antenna improves the features of a common linear monopole. The radiation resistance is increased and the Q is reduced at each fractal iteration, approaching the fundamental limit on small antennas.Peer ReviewedPostprint (published version

    Density of States of Quantum Spin Systems from Isotropic Entanglement

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    We propose a method which we call "Isotropic Entanglement" (IE), that predicts the eigenvalue distribution of quantum many body (spin) systems (QMBS) with generic interactions. We interpolate between two known approximations by matching fourth moments. Though, such problems can be QMA-complete, our examples show that IE provides an accurate picture of the spectra well beyond what one expects from the first four moments alone. We further show that the interpolation is universal, i.e., independent of the choice of local terms.Comment: 4+ pages, content is as in the published versio

    Towards a climatology of sensitivities of Mediterranean high impact weather ? first approach

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    International audienceDuring recent years, great interest has grown within the operational weather community on the adaptable component of observational networks. Decisions regarding where to deploy new observations of special value under threatening weather, or regarding permanent changes in observational strategies need support from sensitivity studies that determine areas where the addition of observations would optimally improve the skill of numerical predictions. Within the context of the MEDEX project (http://medex.inm.uib.es), the sensitivities of a collection of severe weather episodes in the Mediterranean have been computed using the MM5 Adjoint Modeling system. Various approaches are explored trying to summarize the results for the diversity of cases that produce high impact weather (HIW; mainly heavy rain and strong winds) in the Mediterranean region. A first attempt uses an objective classification of the trajectories of the most intense cyclone types from the ERA-40 reanalyses. Sensitivities are then computed for each group of frequent trajectories, providing a prototype sensitivity field for each of the most frequent intense cyclones in the Mediterranean. However, a large portion of HIW episodes in the Mediterranean are not linked to significantly intense cyclones within the climatology. Consequently, a subjective classification of HIW events is also performed and the sensitivity fields for an example case is shown to complete the study. Although the sensitive areas for Mediterranean HIW are not particularly confined, it is remarkable how poorly sampled areas by the regular observing networks such as North Africa and the eastern North-Atlantic are highlighted in the results

    Numerical analysis of the vibrational behavior of the moving assembly of a dynamic loudspeaker

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    En este trabajo se describe el proceso llevado a cabo para analizar numéricamente mediante el método de los elementos finitos (MEF) el comportamiento vibratorio del conjunto móvil de un altavoz dinámico de bobina con doble suspensión inferior y en ausencia de la superior. El estudio se centra en el rango de baja frecuencia. El calibrado del modelo se realiza en base a medidas experimentales de la frecuencia de resonancia y desplazamiento del diafragma. Se hace énfasis en la importancia de los factores de participación asociados a la fuerza de excitación y en los cambios que se producen en estos al introducir fuerzas no equilibradas. Así mismo, el análisis proporciona datos para decidir sobre la distancia entre suspensiones, su número óptimo de pliegues y la ubicación de las trencillas, siendo estos parámetros de gran interés en el diseño de este tipo de altavoces.This paper describes the process undertaken to analyze numerically the vibrational behavior of the moving assembly of a dynamic loudspeaker with double bottom suspension and in the absence of the above one using the finite element method (FEM). The study focuses on the low frequency range. Model calibration was performed based on experimental measurements of the resonance frequency and diaphragm displacement. The importance of the participation factors associated to the excitation force and the changes produced in these when unbalanced forces are introduced are emphasized. The analysis also provides data to decide on the distance between suspensions, their optimal number of folds and the placement of the lead wires, parameters of great interest on the design of this type of loudspeakers.Peer Reviewe

    Analysis of the environments of seven Mediterranean tropical-like storms using an axisymmetric, nonhydrostatic, cloud resolving model

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    Tropical-like storms on the Mediterranean Sea are occasionally observed on satellite images, often with a clear eye surrounded by an axysimmetric cloud structure. These storms sometimes attain hurricane intensity and can severely affect coastal lands. A deep, cut-off, cold-core low is usually observed at mid-upper tropospheric levels in association with the development of these tropical-like systems. In this study we attempt to apply some tools previously used in studies of tropical hurricanes to characterise the environments in which seven known Mediterranean events developed. In particular, an axisymmetric, nonhydrostatic, cloud resolving model is applied to simulate the tropical-like storm genesis and evolution. Results are compared to surface observations when landfall occurred and with satellite microwave derived wind speed measurements over the sea. Finally, sensitivities of the numerical simulations to different factors (e.g. sea surface temperature, vertical humidity profile and size of the initial precursor of the storm) are examined

    Predictability of prototype flash flood events in the Western Mediterranean under uncertainties of the precursor upper-level disturbance

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    International audienceThe HYDROPTIMET case studies 9-10/06/2000 Catalogne, 8-9/09/2002 Cévennes and 24-26/11/2002 Piémont encompass prototype flash-flood situations in the western Mediterranean, attending to the relevant synoptic and mesoscale signatures identified on the meteorological charts. A prominent mid-tropospheric trough or cut-off low can be identified in all events prior and during the period of heavy rains, which clearly served as the precursor agent for the onset of the flash-flood conditions and the cyclogenesis at low levels. Being aware of the uncertainty in the representation of the upper-level disturbance and the necessity to cope with it within the operational context when attempting to issue short to mid-range numerical weather predictions of these high impact weather events, a systematic exploration of the predictability of the three selected case studies, subject to uncertainties in the representation of the upper-level precursor disturbance, is carried out in this paper by means of numerical simulations

    Multi-scale modelling of the dynamics of cell colonies:insights into cell-adhesion forces and cancer invasion from in silico simulations

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    Studying the biophysical interactions between cells is crucial to understanding how normal tissue develops, how it is structured and also when malfunctions occur. Traditional experiments try to infer events at the tissue level after observing the behaviour of and interactions between individual cells. This approach assumes that cells behave in the same biophysical manner in isolated experiments as they do within colonies and tissues. In this paper, we develop a multi-scale multi-compartment mathematical model that accounts for the principal biophysical interactions and adhesion pathways not only at a cell-cell level but also at the level of cell colonies (in contrast to the traditional approach). Our results suggest that adhesion/separation forces between cells may be lower in cell colonies than traditional isolated single-cell experiments infer. As a consequence, isolated single-cell experiments may be insufficient to deduce important biological processes such as single-cell invasion after detachment from a solid tumour. The simulations further show that kinetic rates and cell biophysical characteristics such as pressure-related cell-cycle arrest have a major influence on cell colony patterns and can allow for the development of protrusive cellular structures as seen in invasive cancer cell lines independent of expression levels of pro-invasion molecules.Publisher PDFPeer reviewe

    Hydrogen production by photoreforming of organic compounds

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    Productivity with respect to direct water photosplitting. Methanol is used here as model molecule to investigate the effect of catalyst composition and of substrate concentration on photocatalytic activity. Simple catalysts formulations were selected, in order to propose an easily scalable technology with a poorly expensive material. TiO2 with different structure (anatase, rutile and a mixture of them) was used as semiconductor, doped with a small amount of Au (0.1 wt%) to improve the lifetime of photogenerated charges. A new photoreactor was set up, with external irradiation that improves the scale up feasibility and possible future application with solar energy. Methanol conversion and hydrogen productivity increased with increasing methanol concentration up to 15 wt%. Rutile led to the highest conversion, but TiO2 P25 showed the highest hydrogen productivity. The best result was achieved by treating a 15 wt% methanol solution with 0.1 wt%Au/TiO2 P25, which led to 0.276 mol H2 h-1 kgcat-1
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