8,820 research outputs found

    From the Schwarzschild Anti de Sitter Black Hole to the Conformal Field Theory

    Get PDF
    The emergence of the quantum gravitational effects in a very high energy regime necessitates some corrections to the thermodynamics of Black holes. In this letter, we investigate a possible modification to the thermodynamics of Schwarzschild anti de Sitter (SAdS) black holes due to rainbow gravity model. Using the correspondence between a (d+1)−(d+1)-dimensional SAdS black hole and a conformal filed theory in dd-dimensional spacetime, one may find the corrections to the Cardy-Verlinde formula from the modified thermodynamics of the black hole. Furthermore, we show that the corrected Cardy-Verlinde formula can also be derived by redefining the Virasoro operator and the central charge

    Sequence to Sequence Learning for Query Expansion

    Full text link
    Using sequence to sequence algorithms for query expansion has not been explored yet in Information Retrieval literature nor in Question-Answering's. We tried to fill this gap in the literature with a custom Query Expansion engine trained and tested on open datasets. Starting from open datasets, we built a Query Expansion training set using sentence-embeddings-based Keyword Extraction. We therefore assessed the ability of the Sequence to Sequence neural networks to capture expanding relations in the words embeddings' space.Comment: 8 pages, 2 figures, AAAI-19 Student Abstract and Poster Progra

    Adaptive Behaviours and Occupancy Patterns in UK Primary Schools: Impacts on Comfort and Indoor Quality

    Get PDF
    To improve the quality of school environment and reach state of comfort, it's important that teachers and students take appropriate personal and environmental adaptive behaviours. Studies on adaptive behaviours are mainly focused on adults, especially in residential and office buildings while children's adaptive behaviours at schools are not largely studied. This paper has investigated adaptive behaviours, influential factors and their impact on comfort and indoor quality by doing field studies in 4 primary schools and 15 classrooms in Coventry, UK during July, September, October and November 2017 through observations, subjective and objective measurements. The results are derived from observations on around 400 students aged 9-11 and from more than 600 surveys. Results illustrate that students usually take personal adaptive behaviours after or before breaks, and the number of these behaviours increases during warmer seasons and in afternoon sessions. Students' decisions over appropriate clothing level is related to time of year, however, 27% of students could improve their thermal vote by taking off or taking on jumpers/cardigans. Some environmental adaptive behaviours like door operation are less related to climatic factors, however, window operation is correlated to indoor temperature (R =0.29) and outdoor temperature (R =0.35). Observations show that around 80% of all environmental adaptive behaviours are done by teachers, teacher assistants or on their request, which can provide conditions that are not comfortable for children. Therefore, it is important to facilitate adaptive behaviour of children to improve their comfort level

    Environment of The Gamma-Ray Burst GRB971214 : A Giant H II Region surrounded by A Galactic Supershell

    Get PDF
    Among a number of gamma ray bursts whose host galaxies are known, GRB971214 stands out for its high redshift z≥3z\ge 3 and the Lyα\alpha emission line having a P-Cygni type profile, which is interpreted to be a direct consequence of the expanding supershell. From a profile fitting analysis we estimate the expansion velocity of the supershell v_{exp} = 1500\kms and the neutral column density N_{HI}=10^{20}\cm^{-2}. The redshift z=3.418z=3.418 of the host galaxy proposed by Kulkarni et al. (1998) has been revised to be z=3.425z=3.425 from our profile analysis. The observed Lyα\alpha profile is fitted well by a Gaussian curve, which yields the Lyα\alpha luminosity L_{Ly\alpha}=(1.8\pm0.8)\times10^{42}\ergs \s^{-1}. Assuming that the photon source is a giant H II region, we deduce the electron number density in the H II region n_e=(40\pm10) ({R \over {100 \pc}})^{-1.5}\cm^{-3}, which corresponds to the illumination by about 10410^4 O5 stars. We estimate the star-formation rate to be R_{SF} = (7\pm3){\rm M}_\odot\yr^{-1} with the internal and the Galactic extinction corrected. The theory on the evolution of supernova remnants is used to propose that the supershell is at the adiabatic phase, with its radius R = 18 E_{53}^{1/2} \pc, its age $t = 4.7\times10^3\ E_{53}^{1/2} \yrs,andthedensityoftheambientmedium, and the density of the ambient medium n_1 = 5.4\ E_{53}^{-1/2}\cm^{-3},where, where E_{53}= E/10^{53}\ergs.Andweestimatethekineticenergyofthesupershelltobe.And we estimate the kinetic energy of the supershell to be E_k=7.3\times10^{52} E_{53} \ergs$. These values are consistent with the hypothesis that the supershell is the remnant of a gamma ray burst.Comment: 5 papges, 3 figures, Accepted for publication in Astrophysical Journal Letter
    • …
    corecore