The role of snow cover in the Northern Hemisphere winter to summer transition

This paper examines the role of North Hemisphere snow cover in the linkage between the winter North Atlantic Oscillation (NAO) and the summer Northern Annular Mode (NAM). This transition is partially supported by the persistence of the NAO-induced snow cover anomalies and the asymmetric thermal distribution induced by summer snow cover. We define an index of subpolar temperature difference which links winter NAO with the subsequent summer NAM. The index is also significant in the linkage between summer and winter climates and can be used as an useful predictor of the upcoming winter NAO

Uso de hardware gráfico para la aceleración de métodos algebraicos de recontrucción

El objetivo de este proyecto ha sido implementar un algoritmo de reconstrucción algebraica (en paricular SART, Simultaneous Algebraic Reconstruction Technique) y acelerar su ejecución utilizando los recursos paralelos que ponen a disosición del programador las unidades de procesamiento gráfico de hoy en día. Para ello, primero se han desarrollado dos variantes del algoritmo que sólo utilizan la CPU, en las que nos hemos basado para posteriormente portar a la GPU las partes susceptibles de obtener una mejora substancial de velocidad. Por último, se ha analizado en ambas variantes la calidad de la reconstrucciones y el spedup obtenido respecto a las implementaciones en CPU, así como el impacto en la calidad de los diversos parámetros configurables del algoritmo. [ABSTRACT] The aim of our project has been the implementation of an algebraic reconstrution algorithm (known as SART, Simultaneous Algebraic Reconstruction Technique) and improvement of its running time by making use of the massively parallel computational resources which today's graphics processing units provide the programmer with. To this end, two variants of the algorithm have first been developed which are executed entirely on the CPU, and upon whch we have based our subsequent porting to the GPU of those parts having the potencial to enjoy a subsancial increase in speed. Finally, the quality of both variants' reconstructions has been analyzed, along with the speedup obtained over CPU implementations and the impact that various customizable parameters of the algorithm have on image quality

A complete gauge-invariant formalism for arbitrary second-order perturbations of a Schwarzschild black hole

Using recently developed efficient symbolic manipulations tools, we present a general gauge-invariant formalism to study arbitrary radiative $(l\geq 2)$ second-order perturbations of a Schwarzschild black hole. In particular, we construct the second order Zerilli and Regge-Wheeler equations under the presence of any two first-order modes, reconstruct the perturbed metric in terms of the master scalars, and compute the radiated energy at null infinity. The results of this paper enable systematic studies of generic second order perturbations of the Schwarzschild spacetime. In particular, studies of mode-mode coupling and non-linear effects in gravitational radiation, the second-order stability of the Schwarzschild spacetime, or the geometry of the black hole horizon.Comment: 14 page

Nonlinear quantum optics in the (ultra)strong light-matter coupling

The propagation of $N$ photons in one dimensional waveguides coupled to $M$ qubits is discussed, both in the strong and ultrastrong qubit-waveguide coupling. Special emphasis is placed on the characterisation of the nonlinear response and its linear limit for the scattered photons as a function of $N$, $M$, qubit inter distance and light-matter coupling. The quantum evolution is numerically solved via the Matrix Product States technique. Both the time evolution for the field and qubits is computed. The nonlinear character (as a function of $N/M$) depends on the computed observable. While perfect reflection is obtained for $N/M \cong 1$, photon-photon correlations are still resolved for ratios $N/M= 2/20$. Inter-qubit distance enhances the nonlinear response. Moving to the ultrastrong coupling regime, we observe that inelastic processes are \emph{robust} against the number of qubits and that the qubit-qubit interaction mediated by the photons is qualitatively modified. The theory developed in this work modelises experiments in circuit QED, photonic crystals and dielectric waveguides.Comment: Comments are wellcom

Scattering in the ultrastrong regime: nonlinear optics with one photon

The scattering of a flying photon by a two-level system ultrastrongly coupled to a one-dimensional photonic waveguide is studied numerically. The photonic medium is modeled as an array of coupled cavities and the whole system is analyzed beyond the rotating wave approximation using Matrix Product States. It is found that the scattering is strongly influenced by the single- and multi-photon dressed bound states present in the system. In the ultrastrong coupling regime a new channel for inelastic scattering appears, where an incident photon deposits energy into the qubit, exciting a photon-bound state, and escaping with a lower frequency. This single-photon nonlinear frequency conversion process can reach up to 50\% efficiency. Other remarkable features in the scattering induced by counter-rotating terms are a blueshift of the reflection resonance and a Fano resonance due to long-lived excited statesComment: 5+4 page

One- and two-photon scattering from generalized V-type atoms

The one- and two-photon scattering matrix S is obtained analytically for a one-dimensional waveguide and a point-like scatterer with N excited levels (generalized V -type atom). We argue that the two-photon scattering matrix contains sufficient information to distinguish between different level structures which are equivalent for single-photon scattering, such as a V -atom with N = 2 excited levels and two two-level systems. In particular, we show that the scattering with the V -type atom exhibits a destructive interference effect leading to two-photon Coupled-Resonator-Induced Transparency, where the nonlinear part of the two-photon scattering matrix vanishes when each incident photon fulfills a single-photon condition for transparency

Single photons by quenching the vacuum

Heisenberg's uncertainty principle implies that the quantum vacuum is not empty but fluctuates. These fluctuations can be converted into radiation through nonadiabatic changes in the Hamiltonian. Here, we discuss how to control this vacuum radiation, engineering a single-photon emitter out of a two-level system (2LS) ultrastrongly coupled to a finite-band waveguide in a vacuum state. More precisely, we show the 2LS nonlinearity shapes the vacuum radiation into a nonGaussian superposition of even and odd cat states. When the 2LS bare frequency lays within the band gaps, this emission can be well approximated by individual photons. This picture is confirmed by a characterization of the ground and bound states, and a study of the dynamics with matrix product states and polaron Hamiltonian methods.Comment: 9 pages, 10 figure

Increased moral condemnation of accidental harm in institutionalized adolescents

Social deprivation, as faced by children in institutional rearing, involves socio-cognitive deficits that may persist into adolescence. In particular, two relevant domains which prove sensitive to pre-adult neurodevelopment are theory of mind (ToM) and moral judgment (a complex skill which partially depend upon ToM). However, no study has assessed moral evaluation in adolescents with a history of institutional care, let alone its relationship with ToM skills. The present study aims to bridge this gap, focusing on moral evaluation of harmful actions in institutionalized adolescents (IAs). Relative to adolescents raised with their biological families, IAs exhibited less willingness to exculpate protagonists for accidental harms, suggesting an under-reliance on information about a person’s (innocent) intentions. Moreover, such abnormalities in IAs were associated with ToM impairments. Taken together, our findings extend previous findings of delayed ToM under social deprivation, further showing that the development of moral cognition is also vulnerable to the impact of institutionalization. These results could pave the way for novel research on the role of institutional rearing in ToM and moral development during adolescence.Fil: Baez, Sandra. Universidad de los Andes; ColombiaFil: Herrera, Eduar. Universidad Icesi; ColombiaFil: García, Adolfo Martín. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Instituto de Neurología Cognitiva. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Fundación Favaloro. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt; ArgentinaFil: Huepe, David. Universidad Adolfo Ibañez; ChileFil: Santamaría-García, Hernando. Pontificia Universidad Javeriana; Colombia. Hospital Universitario San Ignacio; ColombiaFil: Ibáñez Barassi, Agustín Mariano. Universidad Autónoma del Caribe; Colombia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Instituto de Neurología Cognitiva. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Fundación Favaloro. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt; Argentina. Universidad Adolfo Ibañez; Chile. Centre of Excellence in Cognition and its Disorders; Australi

Las estrategias publicitarias de las marcas en el contexto de crisis

The economic crisis has shown a situation that had been happening on strategic communication for years: the undermining of the established advertising model. Organizations face a progressive loss of communicative effectiveness of advertising, to the difficulty of connecting emotionally with consumers, the decline of conventional media, to the explosion of the era of personal relations and the hegemony of a citizen, proactive, critical, that it questions the very concept of communication. All this context means that businesses and organizations to redefine their advertising strategies, changing objectives, public values, languages, ways and means to connect with their audiences. The aim of this paper is the study of the major strategic choices that are developing advertising for their brands organizations in the current crisis. To do so, it addresses the analysis of the advertising strategy of a significant sample of the main advertisers on the national scene, representing various sectors of consumption. Through content analysis, discourse analysis combined with the advertising strategies of major brands proceed to the establishment of analytical variables and the categorization of the objectives, strategies, actions and discursive constructions that brands develop their communication policies. The main results of the research are that makes betting on four main types of advertising strategies: the strategy of the U-brands, the defense of traditional brand equity, the strategy focused on price as their main argument and strategy offensive dealer marks around quality.La crisis económica ha evidenciado una situación que venía aconteciendo en la comunicación estratégica desde hace años: el debilitamiento del modelo publicitario establecido. Las organizaciones se enfrentan a una pérdida progresiva de la eficacia comunicativa de la publicidad; a la dificultad de conectar emocionalmente con sus consumidores; al retroceso de los medios convencionales; a la explosión de la era de las relaciones personales y a la hegemonía de un ciudadano, proactivo y crítico, que replantea el propio concepto de comunicación. Todo este contexto hace que las empresas y organizaciones redefinan sus estrategias publicitarias, modificando objetivos, públicos, valores, lenguajes, medios y modos de contactar con sus públicos. El objetivo de este artículo es el estudio de las principales opciones estratégicas publicitarias que están desarrollando las organizaciones para sus marcas en el actual contexto de crisis. Para ello, se aborda el análisis de la estrategia publicitaria de una muestra significativa de los principales anunciantes del panorama nacional, representando a diferentes sectores de consumo. Mediante el análisis de contenido, combinado con análisis del discurso de las estrategias publicitarias de las principales marcas, procedemos al establecimiento de variables de análisis y a la categorización de los objetivos, estrategias, acciones y construcciones discursivas que las marcas desarrollan en sus políticas de comunicación. Los resultados de la investigación permiten concluir que las marcas están apostando por cuatro principales tipos de estrategias publicitarias: la estrategia de construcción de las U-brands, la defensa del valor de la marca tradicional, la estrategia centrada en el precio como principal argumento y la estrategia ofensiva de las marcas de distribuidor en torno a la calidad