19,797 research outputs found

    Superconducting charge qubits from a microscopic many-body perspective

    Full text link
    The quantised Josephson junction equation that underpins the behaviour of charge qubits and other tunnel devices is usually derived through cannonical quantisation of the classical macroscopic Josephson relations. However, this approach may neglect effects due to the fact that the charge qubit consists of a superconducting island of finite size connected to a large superconductor. We show that the well known quantised Josephson equation can be derived directly and simply from a microscopic many-body Hamiltonian. By choosing the appropriate strong coupling limit we produce a highly simplified Hamiltonian that nevertheless allows us to go beyond the mean field limit and predict further finite-size terms in addition to the basic equation.Comment: Accepted for J Phys Condensed Matte

    Alfred-Donat Agache urban proposal for Costa do Sol from the territory to the city

    Get PDF
    This paper reviews the development of Costa do Sol, as planned by architect urbanist Alfred-Donat Agache, for Lisbon Region in Portugal. The Plano Expansão Região Oeste de Lisboa (1934-1936) prepared by Agache and requested by Portuguese Minister of Public Works, Duarte Pacheco will be analyzed. This paper aims also to identify the principles and the theoretical foundations that have determined Agache urban vision for Lisbon City and its Territory. Finally, this paper aims to demonstrate that Alfred-Donat Agache methodological framework has applied Frederick Le Play socio-economic scientific approach. Such approach has informed the construction of a ‘civic’ urbanism that will be identified and analyzed. Two main goals seem to have guided Agache work at Costa do Sol: (i) the fully urban analysis of the city, throughout its social, economic, geographic and urban conditions (past and present) and (ii) the need to expose such analysis to the city’s inhabitants. Finally, this paper demonstrates Costa do Sol proposal to testify a comprehensive understanding of three distinct scales: (i) the territory; (ii) the city; (iii) but also the urban form. The acknowledgment of Agache ‘civic’ urban vision requests a public divulgation to allow the building of Good Practice Lessons for contemporary urban planning theory and practice.info:eu-repo/semantics/publishedVersio

    Hydrodynamics and two-dimensional dark lump solitons for polariton superfluids

    Get PDF
    We study a two-dimensional incoherently pumped exciton-polariton condensate described by an open-dissipative Gross-Pitaevskii equation for the polariton dynamics coupled to a rate equation for the exciton density. Adopting a hydrodynamic approach, we use multiscale expansion methods to derive several models appearing in the context of shallow water waves with viscosity. In particular, we derive a Boussinesq/Benney-Luke–type equation and its far-field expansion in terms of Kadomtsev-Petviashvili-I (KP-I) equations for right- and left-going waves. From the KP-I model, we predict the existence of vorticity-free, weakly (algebraically) localized two-dimensional dark-lump solitons. We find that, in the presence of dissipation, dark lumps exhibit a lifetime three times larger than that of planar dark solitons. Direct numerical simulations show that dark lumps do exist, and their dissipative dynamics is well captured by our analytical approximation. It is also shown that lumplike and vortexlike structures can spontaneously be formed as a result of the transverse “snaking” instability of dark soliton stripes.Europe Union project AEI/FEDER: MAT2016-79866-

    When the Diagnosis is a Victim of the Circumstances

    Get PDF
    Introduction: Haemoptysis is a common symptom which can sometimes mimic gastrointestinal bleeding. Case description: We describe the case of a 31-year-old man who presented to the emergency department after an episode of sudden nausea and presumed massive haematemesis. The situation was interpreted as gastrointestinal bleeding but clinical evolution and greater attention to the anamnesis resulted in a diagnosis of pulmonary tuberculosis and the provision of appropriate care. Discussion: This report emphasizes the difficulty of differentiating between haemoptysis and haematemesis and the importance of a careful anamnesis and attention to all clinical circumstances for an accurate diagnosis. Learning points: Haematemesis and haemoptysis are not always distinguished from each other when a patient's history is being collected.Despite being a rare manifestation of tuberculosis, in the correct epidemiological context, haemoptysis should raise the suspicion of pulmonary tuberculosis.The clinical setting and the need for immediate care should not limit clinical investigation or the differential diagnosis.info:eu-repo/semantics/publishedVersio

    BoWFire: Detection of Fire in Still Images by Integrating Pixel Color and Texture Analysis

    Get PDF
    Emergency events involving fire are potentially harmful, demanding a fast and precise decision making. The use of crowdsourcing image and videos on crisis management systems can aid in these situations by providing more information than verbal/textual descriptions. Due to the usual high volume of data, automatic solutions need to discard non-relevant content without losing relevant information. There are several methods for fire detection on video using color-based models. However, they are not adequate for still image processing, because they can suffer on high false-positive results. These methods also suffer from parameters with little physical meaning, which makes fine tuning a difficult task. In this context, we propose a novel fire detection method for still images that uses classification based on color features combined with texture classification on superpixel regions. Our method uses a reduced number of parameters if compared to previous works, easing the process of fine tuning the method. Results show the effectiveness of our method of reducing false-positives while its precision remains compatible with the state-of-the-art methods.Comment: 8 pages, Proceedings of the 28th SIBGRAPI Conference on Graphics, Patterns and Images, IEEE Pres

    Urban Cholera transmission hotspots and their implications for Reactive Vaccination: evidence from Bissau city, Guinea Bissau

    Get PDF
    Use of cholera vaccines in response to epidemics (reactive vaccination) may provide an effective supplement to traditional control measures. In Haiti, reactive vaccination was considered but, until recently, rejected in part due to limited global supply of vaccine. Using Bissau City, Guinea-Bissau as a case study, we explore neighborhood-level transmission dynamics to understand if, with limited vaccine and likely delays, reactive vaccination can significantly change the course of a cholera epidemic
    corecore