4,089 research outputs found

    Initial conditions for inflation and the energy scale of SUSY-breaking from the (nearly) gaussian sky

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    We show how general initial conditions for small field inflation can be obtained in multi-field models. This is provided by non-linear angular friction terms in the inflaton that provide a phase of non-slow-roll inflation before the slow-roll inflation phase. This in turn provides a natural mechanism to star small-field slow-roll at nearly zero velocity for arbitrary initial conditions. We also show that there is a relation between the scale of SUSY breaking sqrt (f) and the amount of non-gaussian fluctuations generated by the inflaton. In particular, we show that in the local non-gaussian shape there exists the relation sqrt (f) = 10^{13} GeV sqrt (f_NL). With current observational limits from Planck, and adopting the minimum amount of non-gaussian fluctuations allowed by single-field inflation, this provides a very tight constraint for the SUSY breaking energy scale sqrt (f) = 3-7 x 10^{13} GeV at 95% confidence. Further limits, or detection, from next year's Planck polarisation data will further tighten this constraint by a factor of two. We highlight that the key to our approach is to identify the inflaton with the scalar component of the goldstino superfield. This superfield is universal and implements the dynamics of SUSY breaking as well as superconformal breaking.Comment: Invited talk at the BW2013 meetin

    The international law gaze: Marshall Island v United Kingdom

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    The International Court of Justice recently bowed to nuclear weapons States and disappointed the rest of the international community. Forty-two years after the Court’s astonishing decision in declaring the dispute on nuclear tests between New Zealand and France terminated (Nuclear Test Case (New Zealand v. France), [1974] I.C.J. Rep. 458, at [54]), a new chapter on the reluctance of the Court to deal with nuclear weapons took place in its judgment of 5 October 2016 on Preliminary Objections in Obligations Concerning Negotiations Relating to Cessation of the Nuclear Arms Race and to Nuclear Disarmament (Marshall Islands v United Kingdom). There, the Court declared that it lacked jurisdiction, since there was no dispute between the parties. (Marshall Islands v UK, at [59])

    Class-Weighted Convolutional Features for Visual Instance Search

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    Image retrieval in realistic scenarios targets large dynamic datasets of unlabeled images. In these cases, training or fine-tuning a model every time new images are added to the database is neither efficient nor scalable. Convolutional neural networks trained for image classification over large datasets have been proven effective feature extractors for image retrieval. The most successful approaches are based on encoding the activations of convolutional layers, as they convey the image spatial information. In this paper, we go beyond this spatial information and propose a local-aware encoding of convolutional features based on semantic information predicted in the target image. To this end, we obtain the most discriminative regions of an image using Class Activation Maps (CAMs). CAMs are based on the knowledge contained in the network and therefore, our approach, has the additional advantage of not requiring external information. In addition, we use CAMs to generate object proposals during an unsupervised re-ranking stage after a first fast search. Our experiments on two public available datasets for instance retrieval, Oxford5k and Paris6k, demonstrate the competitiveness of our approach outperforming the current state-of-the-art when using off-the-shelf models trained on ImageNet. The source code and model used in this paper are publicly available at http://imatge-upc.github.io/retrieval-2017-cam/.Comment: To appear in the British Machine Vision Conference (BMVC), September 201

    Powering AGNs with super-critical black holes

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    We propose a novel mechanism for powering the central engines of Active Galactic Nuclei through super-critical (type II) black hole collapse. In this picture, ~103M10^3 M_\odot of material collapsing at relativistic speeds can trigger a gravitational shock, which can eject a large percentage of the collapsing matter at relativistic speeds, leaving behind a "light" black hole. In the presence of a poloidal magnetic field, the plasma collimates along two jets, and the associated electron synchrotron radiation can easily account for the observed radio luminosities, sizes and durations of AGN jets. For Lorentz factors of order 100 and magnetic fields of a few hundred μG\mu G, synchrotron electrons can shine for 10610^6 yrs, producing jets of sizes of order 100 kpc. This mechanism may also be relevant for Gamma Ray Bursts and, in the absence of magnetic field, supernova explosions.Comment: 4 pages, 1 figur

    Estudio semiótico del pasquín virtual en las elecciones presidenciales de México 2012

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    El Pasquín es un sustantivo masculino un cartel, cedulón que es un medio de comunicación masivo que llega a un gran número de personas. Los pasquines han sido de gran ayuda para dar información oportuna y no requerida. Su importancia radica en la escala con la que pueden llegar y ser conocidos por el público

    The bias of weighted dark matter halos from peak theory

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    We give an analytical form for the weighted correlation function of peaks in a Gaussian random field. In a cosmological context, this approach strictly describes the formation bias and is the main result here. Nevertheless, we show its validity and applicability to the evolved cosmological density field and halo field, using Gaussian random field realisations and dark matter N-body numerical simulations. Using this result from peak theory we compute the bias of peaks (and dark matter halos) and show that it reproduces results from the simulations at the O(10%){\mathcal O}(10\%) level. Our analytical formula for the bias predicts a scale-dependent bias with two characteristics: a broad band shape which, however, is most affected by the choice of weighting scheme and evolution bias, and a more robust, narrow feature localised at the BAO scale, an effect that is confirmed in simulations. This scale-dependent bias smooths the BAO feature but, conveniently, does not move it. We provide a simple analytic formula to describe this effect. We envision that our analytic solution will be of use for galaxy surveys that exploit galaxy clustering.Comment: Submitted to MNRA

    Transporte y movilidad en el marco de la sustentabilidad y competitividad de la ciudad posmoderna

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    La dinámica urbana depende de tres tipos de factores: físicos, funcionales y morales. Cada uno de ellos representa una dimensión de análisis de la ciudad. El transporte urbano en es un componente de la dimensión funcional, el comportamiento de los individuos se relaciona con la dimensión moral y las características locacionales de los usos del suelo y la infraestructura se asocian con la dimensión física. El propósito del presente trabajo es exponer las características y el papel del transporte urbano de pasajeros en la movilidad de la ciudad posmoderna en el marco de los discursos sobre la sustentabilidad y la competitividad urbanas bajo el análisis de los factores físicos, funcionales y morales mencionados anteriormente.La dinámica urbana depende de tres tipos de factores: físicos, funcionales y morales. Cada uno de ellos representa una dimensión de análisis de la ciudad. El transporte urbano en es un componente de la dimensión funcional, el comportamiento de los individuos se relaciona con la dimensión moral y las características locacionales de los usos del suelo y la infraestructura se asocian con la dimensión física. El propósito del presente trabajo es exponer las características y el papel del transporte urbano de pasajeros en la movilidad de la ciudad posmoderna en el marco de los discursos sobre la sustentabilidad y la competitividad urbanas bajo el análisis de los factores físicos, funcionales y morales mencionados anteriormente

    The International Law Gaze: The ICSID Award in Philip Morris v Uruguay and the Near End of the “Aesthetic Experience”.

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    It was the large economic value of tobacco’s “aesthetic experience” that Philip Morris (PM) sought to preserve in its litigation against Uruguay before an international tribunal operating under the jurisdiction of the International Centre for the Settlement of Investment Disputes (ICSID). There, PM claimed that Uruguay was in violation of the Agreement between the Swiss Confederation and the Oriental Republic of Uruguay on the Reciprocal Promotion and Protection of Investments, dated October 7, 1988 (the BIT). The reason? Uruguay’s decision to enact tobacco control measures, in particular, its single presentation requirement (SPR) prohibiting tobacco manufacturers from selling more than one variant of cigarette per brand family and the increase in the size of health warnings included on cigarette packets from 50% to 80% of the surface of the front and the back (80/80 Regulation). As a result, manufacturers had only 20% of the room on cigarette packs for trademarks, logos, and other information
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