4,609 research outputs found

    Short distances, black holes, and TeV gravity

    Get PDF
    The Hawking effect can be rederived in terms of two-point functions and in such a way that it makes it possible to estimate, within the conventional semiclassical theory, the contribution of ultrashort distances at I+I^+ to the Planckian spectrum. Thermality is preserved for black holes with κlP<<1\kappa l_P << 1. However, deviations from the Planckian spectrum can be found for mini black holes in TeV gravity scenarios, even before reaching the Planck phase.Comment: 4 pages. Contribution to the MG11 Meeting (Berlin, July 2006

    Acceleration radiation, transition probabilities, and trans-Planckian physics

    Get PDF
    An important question in the derivation of the acceleration radiation, which also arises in Hawking's derivation of black hole radiance, is the need to invoke trans-Planckian physics for the quantum field that originates the created quanta. We point out that this issue can be further clarified by reconsidering the analysis in terms of particle detectors, transition probabilities, and local two-point functions. By writing down separate expressions for the spontaneous- and induced-transition probabilities of a uniformly accelerated detector, we show that the bulk of the effect comes from the natural (non trans-Planckian) scale of the problem, which largely diminishes the importance of the trans-Planckian sector. This is so, at least, when trans-Planckian physics is defined in a Lorentz invariant way. This analysis also suggests how to define and estimate the role of trans-Planckian physics in the Hawking effect itself.Comment: 19 page

    Traffic event detection framework using social media

    Get PDF
    This is an accepted manuscript of an article published by IEEE in 2017 IEEE International Conference on Smart Grid and Smart Cities (ICSGSC) on 18/09/2017, available online: https://ieeexplore.ieee.org/document/8038595 The accepted version of the publication may differ from the final published version.© 2017 IEEE. Traffic incidents are one of the leading causes of non-recurrent traffic congestions. By detecting these incidents on time, traffic management agencies can activate strategies to ease congestion and travelers can plan their trip by taking into consideration these factors. In recent years, there has been an increasing interest in Twitter because of the real-time nature of its data. Twitter has been used as a way of predicting revenues, accidents, natural disasters, and traffic. This paper proposes a framework for the real-time detection of traffic events using Twitter data. The methodology consists of a text classification algorithm to identify traffic related tweets. These traffic messages are then geolocated and further classified into positive, negative, or neutral class using sentiment analysis. In addition, stress and relaxation strength detection is performed, with the purpose of further analyzing user emotions within the tweet. Future work will be carried out to implement the proposed framework in the West Midlands area, United Kingdom.Published versio

    Nodal involvement evaluation in advanced cervical cancer: a single institutional experience

    Full text link
    Purpose: To assess the usefulness of different imaging techniques in the detection of nodal involvement in patients with advanced cervical carcinoma. Moreover, to analyze the correlation between the presurgical (FIGO) and postsurgical (pTNM) staging classifications. Materials and Methods: All patients diagnosed with advanced cervical cancer (FIGO Stages IIB-IV) from 2005 to 2012 were selected. The medical charts of 51 patients that underwent presurgical assessment with posterior surgical staging by means of paraaortic lymphadenectomy, were reviewed. Nodal status assessment by computed tomography scan (CT scan), magnetic resonance imaging (MRI), positron emission tomography (PET), and sonography was compared, as well as the size given in imaging techniques compared to the final pathologic report information. Results: Presurgical analysis by CT scan, MRI, PET, and sonography showed pelvic nodal involvement in 51.3% of patients, and para-aortic involvement in 30.8% of cases. CT scan showed positive pelvic nodes in 35% of cases, but pathologic confirmation was observed in just 17.6% of cases. However, MRI resulted in higher rates of up to 48.8% of cases. Concerning para-aortic nodal involvement, CT scan showed positive nodes in 25% of cases, MRI in 3.2% of cases, and the pathologic report in 15.6% of cases. The authors found significant differences between staging groups among both classifications (FIGO vs. pTNM; p < 0.001). Eight cases (15.7%) were understaged by FIGO classification. Conclusions: Despite all imaging techniques available, none has demonstrated to be efficient enough to avoid the systematic study of para-aortic nodal status by means of surgical evaluatio

    Recordant ("in memoriam" dels que foren i del què fou)

    Get PDF

    Les nouvelles universités de Catalogne

    Get PDF

    La ciutat en el record (VII)

    Get PDF

    Els Baixos obstinats en la pràctica musical a l'escola : una proposta metodològica

    Get PDF
    En aquest article, després d'analitzar les diferents opcions actuals en la praxi i la interpretació musical dins de l'aula en l'escola primària, s'intenta oferir una metodologia de treball basada en la utilització dels anomenats baixos obstinats. Aquest és el resultat d'una dilatada experiència personal de l'autor en els camps de la interpretació de la música renaixentista i barroca, així com de la docència en centres d'ensenyament secundari. S'analitzen els objectius i els avantatges pedagògics que aquest procediment ens ofereix per tal de brindar al docent especialista en música una eina que facilita, agilitza i acosta una vivència musical extraordinàriament satisfactòria a l'infant.In this article, after analysing the different current options in the practice and and performance of music in primary school, the author offers a working methodology based on the use of the so-called basso ostinato. This is the result of the author’s longstanding experience in the fields of performance of Renaissance and Baroque music and in secondary teaching centres. He analyses the pedagogical objectives and the advantages this procedure offers, in order to give the specialist music teacher a tool that flexibly provides children with a an extraordinarily satisfactory musical experience

    EDITORIAL. El doctor Pedro i Pons: Una figura irrepetible.

    Get PDF
    corecore