1,198 research outputs found

    Non-existence of multiple-black-hole solutions close to Kerr-Newman

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    We show that a stationary asymptotically flat electro-vacuum solution of Einstein's equations that is everywhere locally "almost isometric" to a Kerr-Newman solution cannot admit more than one event horizon. Axial symmetry is not assumed. In particular this implies that the assumption of a single event horizon in Alexakis-Ionescu-Klainerman's proof of perturbative uniqueness of Kerr black holes is in fact unnecessary.Comment: Version 2: improved presentation; no changes to the result. Version 3: corrected an oversight in the historical review. Version 4: version accepted for publicatio

    Angular distributions in the radiative decays of the 3D3^3D_3 state of charmonium originating from polarized pˉp\bar{p}p collisions

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    Using the helicity formalism, we calculate the combined angular distribution function of the two gamma photons (γ1\gamma_1 and γ2\gamma_2) and the electron (ee^-) in the triple cascade process pˉp3D33P2+γ1(ψ+γ2)+γ1(e+e+)+γ2+γ1\bar{p}p\rightarrow{}^3D_3\rightarrow{}^3P_2+\gamma_1\rightarrow(\psi+\gamma_2) +\gamma_1 \rightarrow (e^- + e^+) +\gamma_2 +\gamma_1, when pˉ\bar{p} and pp are arbitrarily polarized. We also derive six different partially integrated angular distribution functions which give the angular distributions of one or two particles in the final state. Our results show that by measuring the two-particle angular distribution of γ1\gamma_1 and γ2\gamma_2 and that of γ2\gamma_2 and ee^-, one can determine the relative magnitudes as well as the relative phases of all the helicity amplitudes in the two charmonium radiative transitions 3D33P2+γ1{}^3D_3\rightarrow{}^3P_2+\gamma_1 and 3P2ψ+γ2^3P_2\rightarrow \psi+\gamma_2.Comment: arXiv admin note: substantial text overlap with arXiv:1311.464

    Angular distributions of the polarized photons and electron in the decays of the 3D3^3D_3 state of charmonium

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    We calculate the combined angular distribution functions of the polarized photons (γ1\gamma_1 and γ2\gamma_2) and electron (ee^-) produced in the cascade process pˉp\bar{p}p\rightarrow 3D3^3D_3\rightarrow 3P2+γ1^3P_2+\gamma_1\rightarrow (ψ+γ2)+γ1(e++e)+γ1+γ2(\psi+\gamma_2)+\gamma_1\rightarrow(e^++e^-)+\gamma_1+\gamma_2, when the colliding pˉ\bar{p} and pp are unpolarized. Our results are independent of any dynamical models and are expressed in terms of the spherical harmonics whose coefficients are functions of the angular-momentum helicity amplitudes of the individual processes. Once the joint angular distribution of (γ1\gamma_1, γ2\gamma_2) and that of (γ2\gamma_2, ee^-) with the polarization of either one of the two particles are measured, our results will enable one to determine the relative magnitudes as well as the relative phases of all the angular-momentum helicity amplitudes in the radiative decay processes 3D3^3D_3\rightarrow 3P2+γ1^3P_2+\gamma_1 and 3P2ψ+γ2^3P_2\rightarrow\psi+\gamma_2

    Epigenetic Dysregulation in Laryngeal Squamous Cell Carcinoma

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    Laryngeal carcinoma is a common head and neck cancer with poor prognosis. Patients with laryngeal carcinoma usually present late leading to the reduced treatment efficacy and high rate of recurrence. Despite the advance in the use of molecular markers for monitoring human cancers in the past decades, there are still no reliable markers for use to screen laryngeal carcinoma and follow the patients after treatment. Epigenetics emerged as an important field in understanding the biology of the human malignancies. Epigenetic alterations refer to the dysregulation of gene, which do not involve the alterations of the DNA sequence. Major epigenetic changes including methylation imbalance, histone modification, and small RNA dysregulation could play a role in the development of human malignancies. Global epigenetic change is now regarded as a molecular signature of cancer. The characteristics and behavior of a cancer could be predicted based on the specific epigenetic pattern. We here provide a review on the understanding of epigenetic dysregulation in laryngeal carcinoma. Further knowledge on the initiation and progression of laryngeal carcinoma at epigenetic level could promote the translation of the knowledge to clinical use

    3D Echocardiography for Traumatic Tricuspid Regurgitation

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    Telecom InP/InGaAs nanolaser array directly grown on (001) silicon-on-insulator

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    A compact, efficient, and monolithically grown III–V laser source provides an attractive alternative to bonding off-chip lasers for Si photonics research. Although recent demonstrations of microlasers on (001) Si wafers using thick metamorphic buffers are encouraging, scaling down the laser footprint to nanoscale and operating the nanolasers at telecom wavelengths remain significant challenges. Here, we report a monolithically integrated in-plane InP/InGaAs nanolaser array on (001) silicon-on-insulator (SOI) platforms with emission wavelengths covering the entire C band (1.55 μm). Multiple InGaAs quantum wells are embedded in high-quality InP nanoridges by selective-area growth on patterned (001) SOI. Combined with air-cladded InP/Si optical cavities, room-temperature operation at multiple telecom bands is obtained by defining different cavity lengths with lithography. The demonstration of telecom-wavelength monolithic nanolasers on (001) SOI platforms presents an important step towards fully integrated Si photonics circuits

    Cytotoxic activity of kenaf (Hibiscus cannabinus L.) seed extract and oil against human cancer cell lines

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    Objective: To examine the cytotoxic properties of both the kenaf (Hibiscus cannabinus L.) seed extract and kenaf seed oil on human cervical cancer, human breast cancer, human colon cancer and human lung cancer cell lines. Methods: The in vitro cytotoxic activity of the kenaf (Hibiscus cannabinus L.) seed extract and kenaf seed oil on human cancer cell lines was evaluated by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and sulforhodamine B assays. Cell morphological changes were observed by using an inverted light microscope. Results: The kenaf seed extract (KSE) exhibited a lower IC50 than kenaf seed oil (KSO) in all of the cancer cell lines. Morphological alterations in the cell lines after KSE and KSO treatment were observed. KSE and KSO possessed effective cytotoxic activities against all the cell lines been selected. Conclusions: KSE and KSO could be potential sources of natural anti-cancer agents. Further investigations on using kenaf seeds for anti-proliferative properties are warranted
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