2,858 research outputs found

    Corrections to the thermodynamics of Schwarzschild-Tangherlini black hole and the generalized uncertainty principle

    Full text link
    We investigate the thermodynamics of Schwarzschild-Tangherlini black hole in the context of the generalized uncertainty principle. The corrections to the Hawking temperature, entropy and the heat capacity are obtained via the modified Hamilton-Jacobi equation. These modifications show that the GUP changes the evolution of Schwarzschild-Tangherlini black hole. Specially, the GUP effect becomes susceptible when the radius or mass of black hole approach to the order of Planck scale, it stops radiating and leads to black hole remnant. Meanwhile, the Planck scale remnant can be confirmed through the analysis of the heat capacity. Those phenomenons imply that the GUP may give a way to solve the information paradox. Besides, we also investigate the possibilities to observe the black hole at LHC, the results demonstrate that the black hole can not be produced in the recent LHC.Comment: 12 pages, 6 figure

    Periodicities in the occurrence of aurora as indicators of solar variability

    Get PDF
    A compilation of records of the aurora observed in China from the Time of the Legends (2000 - 3000 B.C.) to the mid-18th century has been used to infer the frequencies and strengths of solar activity prior to modern times. A merging of this analysis with auroral and solar activity patterns during the last 200 years provides basically continuous information about solar activity during the last 2000 years. The results show periodicities in solar activity that contain average components with a long period (approx. 412 years), three middle periods (approx. 38 years, approx. 77 years, and approx. 130 years), and the well known short period (approx. 11 years)

    Representation Class and Geometrical Invariants of Quantum States under Local Unitary Transformations

    Full text link
    We investigate the equivalence of bipartite quantum mixed states under local unitary transformations by introducing representation classes from a geometrical approach. It is shown that two bipartite mixed states are equivalent under local unitary transformations if and only if they have the same representation class. Detailed examples are given on calculating representation classes.Comment: 11 page

    Emergence of five kinds of aminoglycoside-modifying enzyme genes simultaneously in a strain of multidrugresistant Escherichia coli in China

    Get PDF
    AbstractA strain of Escherichia coli was positive for 5 aminoglycoside modifying enzyme genes (aac(3)-I, aac(6′)-Ib-cr, ant(3′)-1, aadA5, and aph(3′)-I) in PCR assays. And these positive genes confer resistance to aminoglycosides (gentamicin and tobramycin). This is the first report of emergence of five kinds of aminoglycoside-modifying enzymes genes simultaneously in E. coli worldwide

    Neutron Diffraction Studies of ErNi₅₋ₓCoₓ (X=0.68, 1.68, 2.26) Alloys

    Get PDF
    ErNi5-xCox alloys were prepared by RF induction melting and analyzed using neutron powder diffraction. Rietveld analysis neutron diffraction data indicates the unit cell volume increases with Co content while the a and c lattice parameters show different dependencies on the composition. the Co atoms show higher affinity for the 3g sites than for the 2c sites. the Co sublattice tends to couple antiferromagnetically to the Er sublattice. the easy magnetization direction is along the c axis

    Diuretic Activity of Rubus idaeus L (Rosaceae) in Rats

    Get PDF
    Purpose: To evaluate the diuretic activity of Rubus idaeus L in experimental rats. Methods: Hot-water and methanol extract of three kinds of Rubus idaeus L. fruits were administered to experimental rats orally at a dose of 2 and 5 mg/kg. Hydrochlorothiazide (10 mg/kg) was used as positive control in study. The diuretic effect of the extracts was evaluated by measuring urine volume, sodium and potassium excretion in the urine. Results: Compared with the control group, significant increase in urine volume was observed from the experimental animal treated with wild raspberry methanol extract. In addition, we find that the methanol extract of wild raspberry fruits shows a potassium-conservation diuretic effect, which is a very interesting property in a phytodiuretic. Conclusion: Methanol extract of wild raspberry fruits have diuretic effect on experimental rats. This might be the first formal reports on diuretic effect of raspberry fruits, which can also, to some extent, explain the use of raspberry as a cure for renal diseases in Chinese traditional medical practice.Keywords: Diuretic activity, Rubus idaeus L., Rasberry, Herbal medicine

    Cross-utterance Conditioned Coherent Speech Editing

    Get PDF
    Text-based speech editing systems are developed to enable users to modify speech based on the transcript. Existing state-of-the-art editing systems based on neural networks do partial inferences with no exception, that is, only generate new words that need to be replaced or inserted. This manner usually leads to the prosody of the edited part being inconsistent with the surrounding speech and a failure to handle the alteration of intonation. To address these problems, we propose a cross-utterance conditioned coherent speech editing system, that first does the entire reasoning at the inference time. Our proposed system can generate speech by utilizing speaker information, context, acoustic features, and the mel-spectrogram from the original audio. Experiments conducted on subjective and objective metrics demonstrate that our approach outperforms the baseline on various editing operations regarding naturalness and prosody consistency

    Lighting Condition Analysis for Mars Moon Phobos

    Get PDF
    A manned mission to Phobos may be an important precursor and catalyst for the human exploration of Mars, as it will fully demonstrate the technologies for a successful Mars mission. A comprehensive understanding of Phobos' environment such as lighting condition and gravitational acceleration are essential to the mission success. The lighting condition is one of many critical factors for landing zone selection, vehicle power subsystem design, and surface mobility vehicle path planning. Due to the orbital characteristic of Phobos, the lighting condition will change dramatically from one Martian season to another. This study uses high fidelity computer simulation to investigate the lighting conditions, specifically the solar radiation flux over the surface, on Phobos. Ephemeris data from the Jet Propulsion Laboratory (JPL) DE405 model was used to model the state of the Sun, the Earth, and Mars. An occultation model was developed to simulate Phobos' self-shadowing and its solar eclipses by Mars. The propagated Phobos' state was compared with data from JPL's Horizon system to ensure the accuracy of the result. Results for Phobos lighting condition over one Martian year are presented in this paper, which include length of solar eclipse, average solar radiation intensity, surface exposure time, total maximum solar energy, and total surface solar energy (constrained by incident angle). The results show that Phobos' solar eclipse time changes throughout the Martian year with the maximum eclipse time occurring during the Martian spring and fall equinox and no solar eclipse during the Martian summer and winter solstice. Solar radiation intensity is close to minimum at the summer solstice and close to maximum at the winter solstice. Total surface exposure time is longer near the north pole and around the anti- Mars point. Total maximum solar energy is larger around the anti-Mars point. Total surface solar energy is higher around the anti-Mars point near the equator. The results from this study and others like it will be important in determining landing site selection, vehicle system design and mission operations for the human exploration of Phobos and subsequently Mars

    Lighting Condition Analysis for Mars' Moon Phobos

    Get PDF
    This study used high fidelity computer simulation to investigate the lighting conditions, specifically the solar radiation flux over the surface, on Phobos. Ephemeris data from the Jet Propulsion Laboratory (JPL) DE405 model was used to model the state of the Sun, Earth, Moon, and Mars. An occultation model was developed to simulate Phobos' self-shadowing and its solar eclipses by Mars. The propagated Phobos state was compared with data from JPL's Horizon system to ensure the accuracy of the result. Results for Phobos lighting conditions over one Martian year are presented, which include the duration of solar eclipses, average solar radiation intensity, surface exposure time, available energy per unit area for sun tracking arrays, and available energy per unit area for fixed arrays (constrained by incident angle). The results show that: Phobos' solar eclipse time varies throughout the Martian year, with longer eclipse durations during the Martian spring and fall seasons and no eclipses during the Martian summer and winter seasons; solar radiation intensity is close to minimum at the summer solstice and close to maximum at the winter solstice; exposure time per orbit is relatively constant over the surface during the spring and fall but varies with latitude during the summer and winter; and Sun tracking solar arrays generate more energy than a fixed solar array. A usage example of the result is also present in this paper to demonstrate the utility
    corecore